It’s a very mixed bag. You can (technically) do a Pacifist Run in BG3 that leans on conversation to keep earning XP in a game that heavily favors combat rewards.

But without prior experience in the story paths, it can be hard to know who can actually be cajoled and who is innately unreconcileable. Lots of NPCs lie or bluff or just bait you into giving up initiative.

You do get more story in dialogue. So if you don’t mind the odd ambush or icy rebuff, I’d say there’s more to diplomacy than just pain.