Well you don't have to buy it :P I don't think it's the most convenient, and it is a privilege to play any lewd adult game, extra so on a phone! Plus we don't need excuses to charge money for our products, they are good enough that it's worth it.
So the mobile version is just that much superior to the other versions then? I hope so otherwise the extra work doesnt really justify spending extra money on it over the other versions of the game.
Yep! It's the same as the paid supporter version, and you get extra features like touch controls. So if ya want that ya can pay for it, or if not ya can just get the normal free versions.
That somewhat reassuring but touch contorls are a standard in mobile games, so treating it as an "extra feature" doesnt nothing to help justify that version being premium.