Well, it's a personal matter here.
Some will pay since they don't have much time to play and still want ot be competitive. So they drop $$ when they can play to get everything done then.
Some pay just to be competitive, since they can't go about it any other way.
I wouldn't say any one of them is wrong, depends on mindset. In their own mind, they are playing fair and they enjoy it. It's not like they're doing smth illegal here.
On a side note - I do prefer being better by outsmarting ppl. That being said, I don't think ppl have to feel bad or be considered worse just because they pay for the game. I did pay myself in one or two game before, but developer shut down those games in the next 2-3 months. Since then I decided it's not worth it. It's just throwing money out the window.