It's actually a bit economically unwise to not have this game here (or on Steam, for that matter) be paid. PC players aren't going to spend this much time/money on a mobile game anyway. They will buy a 20-30$ game though. So it's not like you'd be losing revenue if you had this buyable for PC as an .exe, you'd be getting more revenue, more recognition and more respect. You know, those things that are usually very valuable for game developers. But you do you. Not like there aren't other ways to play this game for free.