Well, I don't know about it being worth it, either.
Katarina will likely make us jump through a bunch of political hoops in order to further whatever post-war agenda she may have. And for the marriage itself, she's likely going to try to be the one calling the shots. I'm a bit reluctant to bow down to the woman who orchestrated Operation: Child Murder, even if said operation was completely justified.
And Welles... I'm pretty sure I said this before, but I have a feeling she's not going to want to marry anyone until the King passes a reform allowing women to inherit titles/land. She's not going to give up an Earldom and a Colonelcy, when becoming an officer is pretty much her life goal.
Anyone other than them... eh. We won't be inheriting anything, assuming that the Betrothed's family already has a male heir. It might improve our relationship with the spouse's family, but if they are on the same level as wealth of us that pretty much gives us nothing but an extra vote in the Cortes if we are nice enough and persuasive enough to them. Oh... maybe ruthless MCs could plot to kill the male heir so we can inherit their barony?
My god I'm a hypocrite. I condemn Operation: Child Murder, only to immediately suggest Operation: Murder Brother-In-Law.
Then there's the crossdressing Dragoon. I'm actually genuinely intrigued by that one, but we know nothing about her, and if she turns out to be Garret...