The wedgiemaker isn't to protect from water and mud from your back tire, it is to protect your head and chest from rain.
A couple of those posts about stupid bike accessories shared this, but just saying it was stupid was lame:
https://musguard.com
It is a roll-up fender. When you need it it looks like fenders that I have seen for decades, but when you don't need it it rolls up around your bike frame or you can carry it with you.