What BgSt said, you need to hammer the pachinko to win those contests. And while you may use browser tricks to win these contests:
-should a game require outside tricks to win?
-those tricks you can't use on mobile.

As to the selling speed, neither chrome nor firefox can sell at a fast enough speed to get rid of the thousand of items after a pachinko contest. The requests end stacking up and bloating the game just like buying stats used to do(still do?). And you need an autoclicker to do that unless you want to try your luck at RSI or carpal tunnel syndrome.