I play your game on random days, for 1h at least each session. I cant seem to see how this game translates into a "cash grab" mobile version, because the core element of *just chilling while playing* would be lost to me.
A pc version, as you said, would need some tweaking to look more fleshed out and, in my opinion, would need some kind of infinite goal. Take cookie clicker for example, it started as a simple web game, but there is too much to do that a pc version to handle larger numbers was needed. What I mean is that it needs some dopamine rush elements to keep the player engaged and always recieve some kind of reward as an upgrade or something like that. I dont know if Im making sense here, sorry lol
But in the end, your game is just a fine as this simple webgl game. Its fun enough, I would say. My suggestion would be to make new machines. Some easy ones and some complex ones. Im not super familiar with these coin flipper games, since I only saw a couple during my lifetime, so it would be fun to "learn" about these games by playing your game.
This is just my opinion and the game is yours to do whatever you feel right :)