why are they banned?

Pretty sure it's because somebody who runs this on emu may use a modifcation to the game. I'm pretty sure Loadiine GX2 is banned too.

I think getting the game from Wii U USB Helper is not banned.

If i install the game from wii u USB Helper, and i run it on stream it can be verified? (CEMU)

if you install the game on wiiu usb helper and play it on wiiu it's allowed