I think that we should be able to use emulators because I have noticed nothing different and for people like me who struggle to get there Wii working on their capture card should at least be able to use an emulator to have a chance

https://www.speedrun.com/nsmbw/thread/rhxii

This thread explains why emulator is banned: https://www.speedrun.com/nsmbw/thread/rhxii

If it's too long for you to read here's a summary:

• It has always been banned
• It's an unofficial release
• The loads are extremely fast which gives an extremely large advantage
• It's easy to cheat
• There is an unofficial emulator board but it isn't updated often. You can reach out to the owner about it though.

You also don't need a capture card to run on console, you can just point a phone/camera at the screen and that form of proof is perfectly acceptable. You can also run on emulator without submitting but if you have the ability to run on Wii I would highly recommend not doing so, especially if you plan on switching to Wii in the future because emulator input delay is much different.