Because it's quick and easy, and I really like it. I particularly enjoy using the paintbucket tool on artpad.com for backgrounds. If you don't know what that is, just go on that link, click on that paintbucket, and see for yourself. ^_^
Although I'm pretty sure most of you know what it is. Oi.
So, I was wondering does photoshop have a brush like that? I can't find it on my brush settings, but I think I might've overlooked a brush or something. If not, could someone show me where I could download a brush that resembles the artpad paint bucket brush?