It's "fun" to me. Having a halfling leader type that tosses potions to me and at enemies just seems cool. For my rogue I want to set up a "team" that is themed like mercenaries that are morally grey that are going around with her doing jobs and the alchemist seems more along those lines for a leader than a priest or shaman…
Honestly, this leads to my biggest problem with PVP that has gear and stats in it. If not done right then it can be greatly frustrating to try to play simply because you end up with gear being a deciding difference rather than skill. At least until you get to the highest level where everyone is geared the same.