> It's "money" [that] expires

I agree. I can hold my paper cash in my wallet for as long as I like. Having digital money that expires (even if i can "refresh" the validity period) is a no go. It would have to be used like this: need to buy something? load some money on GNU Taler wallet, buy thing, keep GNU Taler wallet empty.

So it would be just cumbersome to use in real life.