It's actually very clever. Lots of people use yubikeys for their jobs so using it as part of a multisig setup gives you plausible deniability: "That's not a hardware wallet that's what I use to sign in to github." It also improves your anonymity set: "Sorry officer, I don't know what you're talking about. I don't even own one of these 'hard wallets' or whatever you called it." 

 Can you make it so that it can actually sign you into GitHub as well as have a multisig part? 

 Yep!