When you have lots of badges, 16 icons is pretty limiting, especially when there are some Font Awesome icons that really suit certain situations. For example, when we give out a badge for installing the experimental version of Windows on your development machine, we can use {icon windows}, which is far more suitable than having most badges with {icon star} because nothing else fits.
I realise there's the usual "we should only have 16 icons so they're unique in the system", as is the case for project icons, but in this case I think it's warranted because badges are ~pretty special~.