Got a Halloween sakura with bad ivs. Kitty paddle fodder or merge?

I know this does not answer your question directly so I apologize in advance, but if it were me, I would do neither. At least not immediately.

If my choices were limited to (1) merge, (2) inherit the weapon, or (3) keep it, I would choose option 3.

I am in a similar boat except I pulled a bad IV summer Elise. I was going to give her skills away, and then I realized that the double SP from her valor skill could be such a nice quality of life tool that I couldn't decide whether to inherit that, or her A skill, or hibiscus tome. I decided to keep her since she's got all 3 and I would lose 2 if she were inherited.

If I use 2 green tomes with valor, that's 4x SP per kill. If I gave a blessing, the blessed unit would earn 8x. On the weekends, 16x. If that unit scored 10 kills on a workout map, it would earn 480sp instead of 30, For the price of 15 stamina or less. That's huge.

If I had an extra Halloween Sakura I might give dagger valor 3 to performing arts olivia.

I might also keep her to see how the meta develops. There are lots of daggers and many of them already have refines that would make an unrefined weapon much less attractive. If peshkatz or poison dagger get a refine, kitty paddle might feel like a waste on them. Likewise, if kitty paddle gets a boost but the boost doesn't make sense to run on one of kagero or sothe for some reason, it might not be worth it in the long run.

And for units that are so rare, a merge just feels bittersweet. sure they're stronger... By like, 1hp and 1def. It might make the difference in corner cases but generally no.

EDIT: Nevermind. I just tested my valor skill idea and I am unable to get the extra sp from the second valor skill. Major let down, but it's consistent with the wording so I should have known. Add me to the list of people wondering what to do with my duplicate seasonal heroes.