They are a mobile game rewards platform that pays in sats and uses nostr for social aspects. Mobile game developers can use them to integrate Bitcoin rewards into their games and ZBD handles all the administration involved in custody and distribution of the rewards. They require some permissions in order to be used like location tracking to prevent abuse of the system (they say they don't sell your data).

You can collect a miniscule amount of sats for playing the games and they also pay you to watch ads. It still doesn't amount to much, but there's people that value their time so low that it's worth it to them. I played one shitcoin mining idle game and was bored out of my mind within an hour and had earned like 50 sats, not enough to even cash out.

I think their target audience is children.