Why does CLN (c-lightning) sync from Genesis while LND only syncs from the wallet's birthday?

I've installed two major Lightning Network implementations, CLN (formerly c-lightning) and LND, with bitcoind testnet as backchain on the same server. On the first startup I noticed CLN synchronizes all blocks from the beginning of the blockchain:

2022-07-05T23:31:29.487Z DEBUG lightningd: Still waiting for initial block download
2022-07-05T23:31:29.593Z DEBUG lightningd: Adding block 1: 00000000b873e79784647a6c82962c70d228557d24a747ea4d1b8bbe878e1206
2022-07-05T23:31:29.647Z DEBUG lightningd: Adding block 2: 000000006c02c8ea6e4ff69651f7fcde348fb9d557a06e6957b65552002a7820
2022-07-05T23:31:29.685Z DEBUG lightningd: Adding block 3: 000000008b896e272758da5297bcd98fdc6d97c9b765ecec401e286dc1fdbe10
2022-07-05T23:31:29.732Z DEBUG lightningd: Adding block 4: 000000008b5d0af9ffb1741e38b17b193bd12d7683401cecd2fd94f548b6e5dd
2022-07-05T23:31:29.752Z DEBUG lightningd: Adding block 5: 00000000bc45ac875fbd34f43f7732789b6ec4e8b5974b4406664a75d43b21a1
2022-07-05T23:31:29.774Z DEBUG lightningd: Adding block 6: 000000006633685edce4fa4d8f12d001781c6849837d1632c4e2dd6ff2090a7b
2022-07-05T23:31:29.792Z DEBUG lightningd: Adding block 7: 00000000e29e3aa65f3d12440eac9081844c464aeba7c6e6121dfc8ac0c02ba6

while LND only scans blocks from the wallet's birthday onwards:

2022-07-05 23:21:55.757 [INF] LTND: Waiting for chain backend to finish sync, start_2284292
2022-07-05 23:21:56.613 [DBG] LNWL: Chain backend synced to tip!
2022-07-05 23:21:56.614 [DBG] LNWL: Locating suitable block for birthday 2022-07-03 15:15:05 -0300 -03 between blocks 0-2284292
2022-07-05 23:21:56.617 [DBG] LNWL: Checking candidate block: 1142146, hash=00000000000bee59e6acdb88deee299fcce4c8603a04a60b022d70f256b4d880, timestamp=2017-06-18 16:00:52 -0300 -03
2022-07-05 23:21:56.619 [DBG] LNWL: Checking candidate block: 1713219, hash=000000000000905bf5e522da9cc5d30a93728feb51f3409396193f120505e2ca, timestamp=2020-04-14 06:51:58 -0300 -03
2022-07-05 23:21:56.621 [DBG] LNWL: Checking candidate block: 1998755, hash=00000000000009aa098093884b3f352bfc1efa24ec2af3d541e2fa2ba7e54d6b, timestamp=2021-06-02 19:57:47 -0300 -03
2022-07-05 23:21:56.623 [DBG] LNWL: Checking candidate block: 2141523, hash=00000000849bdb7b93b3deb7182cb1ec3dc2e470d4359ac6fe67d19e5bd5f84e, timestamp=2022-02-14 17:16:49 -0300 -03
2022-07-05 23:21:56.625 [DBG] LNWL: Checking candidate block: 2212907, hash=00000000000004e43dbee8c2f5ae622bb6a984183ef07a8341b1eec6ce331ce5, timestamp=2022-04-28 00:06:02 -0300 -03
2022-07-05 23:21:56.627 [DBG] LNWL: Checking candidate block: 2248599, hash=00000000000009c8763aaa3757774b8c8611495dd2f190672d1c4084d40368d6, timestamp=2022-05-26 08:36:29 -0300 -03
2022-07-05 23:21:56.629 [DBG] LNWL: Checking candidate block: 2266445, hash=00000000000022f256ef974c1467221afc19f6c087ffb147554191d128099438, timestamp=2022-06-16 10:46:47 -0300 -03
2022-07-05 23:21:56.631 [DBG] LNWL: Checking candidate block: 2275368, hash=0000000000000069a27c710313fc5a764e8bab5fed550af837d0c8b1d6fdd558, timestamp=2022-06-16 14:23:46 -0300 -03
2022-07-05 23:21:56.633 [DBG] LNWL: Checking candidate block: 2279830, hash=00000000000001d54cbb97ed368723e4ae7681f6c3d625d517b9dbe3a7d0678a, timestamp=2022-06-18 00:41:09 -0300 -03
2022-07-05 23:21:56.635 [DBG] LNWL: Checking candidate block: 2282061, hash=00000000000000b1517a474a0c8e32a9bd452bd1117cc2a799195991d10c3306, timestamp=2022-06-23 13:04:59 -0300 -03
2022-07-05 23:21:56.637 [DBG] LNWL: Checking candidate block: 2283176, hash=00000000000000498bf2dbab757cba69b77a8d31ea437b2a377aabdb08c0d3cc, timestamp=2022-06-28 19:37:39 -0300 -03
2022-07-05 23:21:56.639 [DBG] LNWL: Checking candidate block: 2283734, hash=000000000000003a55f287f3243841f215572c092995ccf286d9d92398d21785, timestamp=2022-07-02 14:50:17 -0300 -03
2022-07-05 23:21:56.641 [DBG] LNWL: Checking candidate block: 2284013, hash=000000000000004f39aada91825e5d6121e6d7bcda6be504a6f2c13dac133df9, timestamp=2022-07-04 05:13:13 -0300 -03
2022-07-05 23:21:56.643 [DBG] LNWL: Checking candidate block: 2283873, hash=000000003c07419de729aa383f639e506e24dc5f7e947f80cfaf5d2e67837c43, timestamp=2022-07-03 08:31:57 -0300 -03
2022-07-05 23:21:56.645 [DBG] LNWL: Checking candidate block: 2283943, hash=0000000000000017b3b716a4e380900fbf2e114d2536a6f5e71427e5b10a34f8, timestamp=2022-07-03 17:57:30 -0300 -03
2022-07-05 23:21:56.647 [DBG] LNWL: Checking candidate block: 2283908, hash=000000000000004aef1f2fc4dc6973f7c9ac67e5f6c69e1df089f92c83e91324, timestamp=2022-07-03 13:34:25 -0300 -03
2022-07-05 23:21:56.647 [DBG] LNWL: Found birthday block: 2283908, hash=000000000000004aef1f2fc4dc6973f7c9ac67e5f6c69e1df089f92c83e91324, timestamp=2022-07-03 13:34:25 -0300 -03
2022-07-05 23:21:56.656 [INF] LNWL: Started rescan from block 000000000000004aef1f2fc4dc6973f7c9ac67e5f6c69e1df089f92c83e91324 (height 2283908) for 0 addresses
2022-07-05 23:21:56.687 [INF] LNWL: Catching up block hashes to height 2283919, this might take a while
2022-07-05 23:21:56.693 [INF] LNWL: Done catching up block hashes
2022-07-05 23:21:56.693 [INF] LNWL: Rescanned through block 0000000000000005cdcf62d03147fc812f5b01b21a919bdbe38a3588cafdd5f8 (height 2283919)
2022-07-05 23:21:59.062 [INF] LNWL: Catching up block hashes to height 2284292, this might take a while
2022-07-05 23:21:59.063 [INF] LNWL: Done catching up block hashes
2022-07-05 23:21:59.063 [INF] LNWL: Finished rescan for 0 addresses (synced to block 00000000eb61cbd41eaaa4c3646418dd1acf75d30b04239385b19c51fef43cec, height 2284292)
2022-07-05 23:21:59.785 [INF] LTND: Chain backend is fully synced (end_2284292)!

This seems to give a huge advantage over CLN on first startup times. As of now, my CLN node has spent over 14 hours synchronizing while LND worked in a few seconds. Also, as far I understand, a Lightning node should sync the full UTXO set to verify open channels. But this should be provided by the backchain.

Is there a good reason for CLN to reprocess everything? Also, if LND only syncs from the wallet's birthday, how does it verify channels' funding transactions?

Thanks in advance.

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