They look like they're sailing a ship upon the high seas, don't they? Or harpooning Moby Dick at the very least.
I doubt anything much larger than a dead bird's gotten stuck in that chimney but even so, when you need one, a chimney sweep is a hero equal to any leviathan of literature. It's not like I have a tool long enough to grab whatever's gotten itself lodged in there, do I? And even if I did, I wouldn't want to climb onto the roof to reach for it. And even if I did, what if I failed?
It's like flying a plane, performing surgery or coding html. Some situations require a professional.