It’s like any other creative hobby — woodworking, metalworking (computer programming?) etc. There’s joy in using your hands and brain to make something enjoyable out of low-value materials. There’s joy in being able to show people “Look what I made!”

Creative hobbies do tend to be a bit male-coded or female-coded for various reasons. For some hobbies I suspect that the very single-sexiness of the hobby is part of the appeal — women join knitting circles as an excuse to hang out with other women, men go golfing as a way to hang out with other men.