Because you can't interact with them long-term. They're from different servers, so no guilds, no trades, no meaningful interactions.
For all the more impact they'll have on you, your guild, or your server, they might as well be NPCs.
*shrug* I don't mind the WF/TF system, and really, this is a pre-expansion event. Anything we get now will be obsolete in a month. There's no reason to feel compelled to do any of this unless you [I]want/I] to. In some ways, this is my favorite time of the game.