It's mostly just that I like low level stuff. I'm also a bit obsessed about being the one to make everything in my games. And I'm lazy and can't be bothered to learn engines ^^'
Just to clarify, I haven't made games big enough that they would need actual proper engines with all the cool features, so my "engines" aren't that much of an undertaking. Also, haven't yet made one in a low-level language, just Java and TypeScript so far.