Your `/bin` technique works for Windows as well. I run Hugo for a couple of simple sites from a Windows machine. To do this, simply copy hugo.exe to C:\Windows and call it a day.
You'd be better having it out of the OS directory and a path reference surely, no?
In any case I'd think the drawback to this is the manual updating everytime, although overwriting a single file with curl/wget is probably not much more laborious than updating gems. And less likely to break. And wouldn't have dependency problems during the update.
.. you win this round rocky1138, but don't think this is over!