"I mean, how much difference can it make, and how isn't it cheating ?"
So what are you saying here, that it makes no difference or that it's cheating? I think if curling started now maybe sweeping wouldn't be such a part of the sport but remember it's a game developed on frozen ponds not perfectly polished olympic ice rinks. But these days, it means it's a pretty incredible bit of teamwork to get the stone where you want it to go.
Still dull mind. But not as dull as bowls.