genuine ship related question (new to phighting lore)

I've been thinking about some ships and while I know some are bad for obvious reasons (seeing each as siblings ect)

I just wanted to know if there's a reason why shuriken x katana are like nowhere at all even tho they're neighbors 🥹

I wanna like them purely cus shuriken is one of my mains (plus I low-key relate) and I like katana a lot

but I really would appreciate it if someone can help me understand why that ship is nowhere to be seen or if it's even bad in the first place 🥹