Don't take my comment to be against the idea, it's great to be honest, I'm simply not the target market - however there are quite a few more wealthy, entrepreneur and silicon valley types on here who wouldn't miss a few hundred dollars in tipping.
The idea is definitely a good niche and if I simply had more disposable income I would use it - don't let me refusal discredit it in any way.
Bitcoin would be pretty useless if you couldn't break it up into smaller pieces, especially at the current prices. =) It is divisible up to 0.00000001 (8 decimal places) and the total number that can exist is 21 million (which hasn't been reached yet).
The idea is definitely a good niche and if I simply had more disposable income I would use it - don't let me refusal discredit it in any way.