Comment by delecti

I'm fairly confident you're incorrect. There's a single shared account between the 3DS and Wii U online stores, and I also know for sure that 3DS purchases are tied to your user account, rather than your hardware. I suppose it's possible that it works differently for the Wii U than the 3DS ecosystems, but that seems unlikely. You can still only have an account attached to a single console (of each type) at a time, but if you lose one or it dies, you can reattach your account to the new one.