I'd estimate, that 'working' DAPPs can only be nichy ones w/o any real risk exposure. Similar to bitcoin early bootstrapping with Silkroad you can start with:
Gaming, Betting, Cheating, Porn...
The really big one is truely decentralised poker.
Decentralized poker would be infested with bots and colluders. Even online casinos with proprietary closed source poker clients scanning players' computers for suspicious activity and antifraud/security teams monitoring for botlike behaviour have a bot problem. It would be an awful user experience for a recreational player.