it's sped up, originally 5 mins. you get 900 gralats. making a new email and identifying it on graal could take 3 - 5 mins. You'd get at least 5400 gralats every hour, and transfer them to your main account? don't think they would allow this, ever
there are more chests, but the time one would take to reach them isn't worth it
also, you don't need to wait 24 hours to open chests, you just need to identify your account