Perhaps someone in the beta can answer this. I've been looking into the Garrisons, and I can't figure out how the profession ones are supposed to work.
Say for example, my monk has Herbalism and Enchanting. I can pump herbs I collect into an Alchemy building and have them make stuff for me? That seems to be how it is... you can use them for access to things that character can't normally get on their own.
As for Enchanting, would I want the Enchanting building, or another profession that I don't have access to on that character? I wouldn't be able to supply them with skins or ores, or I would say getting the Leatherworking or Jewelcrafting buildings would be awesome.
I guess tl;dr: are the buildings supposed to compliment what professions you already have, or are they meant to give you access to professions other than your own?
I'm sorry if the answer is out there and I just couldn't find it. I can find what the profession buildings' upgrades do, but not a lot about what you get out of them.