This is a cool and interesting solution, but has trade offs just like any other solution and I think the trade offs are too many for me to fully like it. My main issues are speed and fees. It's only acceptable now. I don't believe fees will always be as low as they are now which makes this very hard for sending small amounts. I don't believe the price of bitcoin be always be this low, so again this makes it incredibly hard for sending small amounts. I could be wrong but I also feel that telling someone I tipped them but due to randomness, they can't use that money for an hour seems like bad experience. Maybe this last one isn't a big deal, because it's a tip and they don't need the funds ASAP. I don't like that we're setting people's keys up to be incredibly more valuable than social communication. I like that this is all part of the conversation. We need to keep having these, because ultimately someone will solve many of these issues and make trade offs minimal.