All in all, I think EmpororIng has the most common answer (Even if that's not the case in this thread).
The other ways of making 2D art involve either buying some expensive stuff such as a decent tablet and Photoshop... or it involves the masochistic practice of drawing on paper, scanning it into a program, and then coloring it in. And just praying that your scanner picks up every line drawn perfectly.
Pixels, on the other hand, are completely native to computers and therefore are bound to be the most common type of drawing in programs. There's tons of free stuff out there that concentrate on this, and that's probably why you see so much of it now.
As for me? I like drawing pixel art because it feels like I have the most control. If I see a mistake or feel my sprite looks bad, it's very easy to edit and I can do it with far more precision than I can with the eraser tool in photoshop or GIMP.
I must admit though, it's very hard for pixel art to stand up to the more popular forms of 2D art today.