I'm honestly surprised anyone is buying WiiU VC titles. With Nintendo still not having a good system to transfer that stuff between consoles via a consistent, shared account, and with the death of the WiiU imminent, it seems silly to invest in much of anything.
This is coming from a bitter ex Wii owner who lost hundreds of dollars in VC titles due to a robbery years ago, though.
The Nintendo ID still saves the purchases, and I think most signs point to VC transferring other to the next generation, at least first party wise, so I don't think it's that big of a deal.