Windows support is huge. One of the barriers to me considering QBE for a project in recent memory was that it had no story for proprietary OSes (Windows, MacOS), and whether I like it or not, those make up the overwhelming majority of desktop-like market share. (this is the same reason I find Hare, a language that builds with QBE, interesting but not practical for my own uses - targeting only Linux and the BSDs is a non-starter, even if I personally am a Linux-only guy)