I will say, the real major reasons I see for not having a web release/demo are usually either A: Game Jam project, there was not time B: Game too fuckin BIG, this is the one that kills so many or leaves the demo stuck in some utterly unrepresentative V0.03 state is that the game’s core is too big for Itch to host Otherwise quite the nice informative post
Glad you found it useful.
Ok, for game jams I think I understand, but there's as much time for things as you make. There's no reason you couldn't pick up a game jam project after the jam, make a web build for it, and watch the analytics to see if you have an engaging product. You already went through all of that effort to do the jam. You might as well get something useful for your business out of it.
The game being too big isn't something I completely understand or relate to, but I'm guessing some engines naturally bloat the size of the game over the 1-2 GB Web Assembly limit. You're not going to like my answer for this. If the game project is important enough, you'll learn how to make the game from scratch so the limit isn't as important or you will figure out how to cut out content that isn't central to the experience to bring it down.
Either way, if you are persistent enough and you care, neither of these should be a concern. You might have other reasons you think the game won't work separate from analytics, but that's more of a gut decision and not a true barrier to getting accurate data on your game's marketability.