That's a good question! Across the four blockchains where I'm active, a nice cross-blockchain community is developing! I know some people on three of the four. I love that, and I want to create more of it!
Well, yes and no. Yes, it's important to keep one's node online as much as possible, which does help progress go faster, but no due to not actually needing to be online at all times. Payouts happen once per day, though when it happens is variable. If you happen to be online when the check is done, you'll get paid, if you're not, you won't.
!LOLZ
!LUV