The simple rebuttal to people saying no-one would spend a deflationary currency: If you knew everything would be 2% cheaper next year, what would you actually stop buying?

People often attack Bitcoin by saying no-one would ever spend it. Well, as it stands now, yes, you'd be stupid to spend your bitcoin. The potential for growth is just too high.

However, it is just a fact that bitcoin cannot continue this growth indefinitely. At some point it will stabilise. It will still be deflationary, but the 50% rises in a year will be a thing of a past. You'll just see small, incremental deflation on a year to year basis (as opposed to fiat which slowly bleeds you out). At that point you can ask: What would you actually stop buying if it will be 2% cheaper next year?

Sure, a currency that deflates 50% a year on average wouldn't be spent. But then, a currency that inflates on average 50% a year is useless too. If you're going to talk about deflationary currency not working, then use deflation figures in line with what you would use for discussing in inflationary currency. Really, deflation or inflation in the range of 0 to 5% isn't going to change many people's purchases. The difference is one allows you to save over the long run, one destroys you over the long run.