I would probably just call it hand coding, as we say we use hand tools in wood working. Many do this for fun, but knowing the hand tools also makes you a better woodworker.

It's an interesting question: Will coding turn out to be more like landscaping, where (referring to the practice specifically of cutting grass) no one uses hand tools (to a first approximation)? Or it will it be more like woodworking, where everyone at least knows where a Stanley hand plane is in their work shop?