Original Wii does not need this adapter so long as they have GC port. This adapter does not work in vWii and original Wii because neither of them can see this adapter when plugged in.
To make this adapter usable on vWii would require several IOS inside vWii to be patched. Setting time consuming / costly effort aside, this goes against the very reason how IOS were set up to begin with. IOS were designed so that new feature requires separate IOS file and that each Wii game was hardcoded to use a specific IOS. A good example is USB 2.0, only exists in IOS58. There are only 3 Wii game using IOS58 so no other Wii game beside those 3 can use USB 2.0.
Nintendo picked this design so that when they introduce new features it does not introduce bugs on old games. In short, making this adapter usable on vWii is possible, but unlikely.