RAM does primarily function how you said Kevin but it also does other things. The processor also contributes to how many programs (or processes) you can do simultaneously.
I think it's good that you can use the PS3 for such powerful computing, but people will start to get the idea it was designed for that purpose and then complain when it doesn't live up to expectations.
When they get bored with black holes and gravity, they could always have a COD4 LAN party.
