Am I right, that people who are not staking 24/7, missing the party and get nothing, because coins age is obsolete?

Simple yet effective solution to the 51% issue. Nice to see progress so often!
Yes, it also invalidates the 'nothing at stake' criticism on PoS. Blackcoin already has this for a while now.
The way I understand it, it still keeps track of the reward you are due so you don't get ripped off. I would imagine if you wanted to test it out for sure, you could purposefully choose not to mint for say 120 days, and then see what the mint reward would be. You should get the full amount of reward anyway.