I honestly don't think they're much more than trophies, besides maybe Performing Azura. Since you got her already, I'd just wait for the next banner, but it's your choice
That was my initial take, but Inigo has been an epic boon to my teams, despite my initial hostility at how bad his stat-line was... as have Azura and Olivia.
Part of me still feels you're right, but I'm just not sure.
I think it's worth going for six dancers total in order to have one for each Arena Assault after the first. But that's just because I love dancers and hate going up against teams running one without having one myself.
I'll wait till the last couple days. I have the most luck on that "one" unit I cant get on the last day. but only sometimes... Shigure might be my Julia/S.Lucina/Sonya/Tana... that unit I cannot have.
From what we've have seen, his skills are incredible, he doesn't even need the best stats to be awesome! I can't wait to put him on my Cavalry team with Eldigan!