Even still, it helps a lot with allowing people to play it on a variety of setups/OSes.
Speaking personally, I tried building my game for HTML and Linux and neither worked. Former I think because of certain programming decisions we made, latter because... I guess something's weird about my distro, I have no idea. I think this is a bit of a GameMaker issue and other engines have better build options & compatibility? But yeah that's why Snack Wanderer is windows download only.