I think they should be delegated to good newbies who join, and removed from newbie spammers.
This is what the Dapps would likely do. The users wouldn't need buy RCs, the Dapps would in the same way a website has a bandwidth usage level that they pay more for depending on traffic.
What it seems to me is that resource credits are an advancement because they make transparent what was already happening before, which is that someone was paying for newbies to join
Yep. This allows for an accurate pricing model too kind of like a water meter on a house.