I don't know why these keep posting as 'guest'. One more try as a logged in member so I actually get email confirmation of any responses.....
The system requirements for the windows store app indicate x86 systems are required. Will the program not work on a 64 bit operating system?
Yes it will. x86 does not mean 32-bit. It broadly means IBM PC-compatible.
So the requirement basically means that you cannot use WinSCP e.g. on Surface tablets or Xbox, which are not IBM PC compatible although they do have Microsoft Store.