There are several features tied to the housing.
-Chocobo Training (When your chocobo hits level 10 you can raise them further to level 20 and even dye them in housing stables)
-Airships (You can build airships and send them on expeditions to bring back rare items or use the airship to get to the diadem without forming a full party in ishgard)
-Orchestrian (Let's you listen to songs outside of an inn room)
-Vendors and other items (Housing allows you to have an armoire, cutscene log, summoning bell for retainers, aethsetician, mender, dye seller, materials vendor, FC bank, mailbox all in one location.)
I may be missing some things, but housing does have many features tied to it that are exclusive only to FC houses. Personal houses are actually lacking some of them.
