Something else to consider is the whole 'public scene' aspect -- I am much more likely to go to a scene in progress somewhere I know is part of the 'public grid' than I am going to be to page someone for RP so I can get a +meetme, or join a room from a list of rooms that I'm not sure is a private scene or what because it's all on a list and are you SURE that I won't be interrupting?
There may not actually be a functional difference between picking a room off a list or just walking into it from the grid, but there are still practical differences to take into consideration.
Yes, once people on a game get established, they're all for asking for +meetmes and joining their friends wherever they are, without a grid...how do you get there? How do you get over being new, a solo player, without an established playgroup? You can't be shy, fuck, no way -- you HAVE to be proactive and ask people directly for RP...