One of the most appealing aspects of 24/7 character advancement, whether one is online or off, is that the player not only feels that he/she is getting their money's worth regardless of how much physical time they have to devote to the game, but they never have to fell like a 2nd-class player, since their characer is advancing at the same rate as anyone else's. This sense of value that continuous character advanceent provides allows the player, when they are actually live and in the game, to do whatever they wish, and do not feel compelled or pressured to "maximize" their online experience with "efficient" playing.
I think that one of the great problems of online gaming is that the mode of character advancement in current MMOGs is detrimental to to all but a very narrow spectrum of playstyles and potential gaming relationships. While those that enjoy and thrive on maximum efficiency effort can well enjoy current MMOG structure, the more casual player, the more social player, and the true role-players are faced with the problem of how to both advance their character efficiently and do other things in the virtual world they find as enjoyable, or even more enjoyable.
With 24/7 character advancement, players no longer have to choose between efficiently advancing their character and doing anything else they wish to do in the game world; they can do both. If they wish to organize or attend some social gathering, they can do so to their heart's content, secure in the knowledge that any such activities do not compromise the advancement of their character whatsoever. Players can explore the world, investigate lore, help other players out, role-play, or just sit in a local tavern and shoot the breeze with friends ... and still advance their character at the same rate as anyone else.
24/7 character advancement offers a radical reinvention of the genre. Seriously, how many people really have the time to devote to such a hobby, which requires huge numbers of hours to invest? To break out into a larger market, the genre needs to reach out to those that have at most a handful of hours per week to invest, but still wish to enjoy the advancement and management of their character's progress in a persistent, online social world.