Some games are free to play with monetization. Its not per user, its per installation, and they count opening a webpage as one. And each reinstall costs 20c, even when its imbedded into webpage, via webgl. Someone opened your game from new browser/different phone/user? -20c from developer. Someone cleaned cookies and opened it in browser? -20c from developer. Someone wrote a script to automate installation/deinstallations? -20c per each iteration. They could literally demand billions from developers using unity engine.