First of all, the CBHC horror stories are probably just people screwing up royally due to user error.Is it safe to install Wii Sports I'm about to install from Teconmoon's Injector? Like could I brick? I've heard horror stories about CBHC but, haven't seen Wupinstaller brick anyone but, this guy on youtube said it could but all installed with Wii U USB Helper wouldn't brick he said IDK what to do, do you?
Also, installing the injected Wii Sports games is completely safe as long as you do not screw it up by doing something that's obviously dangerous (like turning off the console when you're installing the game) And finally, Wii U USB Helper does indeed offer Wii and GameCube injections that were most likely made with this tool to begin with. So in conclusion, you won't brick.