Is there any advantage building up your relationship with non party members?
In P5 everybody you make a relationship with will give you a bonus ability or something.
But in P4 there seems to be no such thing. So is it a good idea to ignore relationships with non-party members (since they don't give you any advantage other than seeing their story?)
At least relationships with team members give them a few bonuses in the dungeons...
Spoiler:
I know I also need to build up relationship with Marie before the epilogue to get the best ending. But except her, anything to get from other non party members?