the less code the better because the more code the higher the maintenance burden
keeping code around isn’t free. it makes refactoring harder, it makes compilation times longer, it makes the kernel larger, it makes it harder to guarantee device compatibility. that’s all part of maintaining software, but it makes no sense to waste work maintaining shit noone is using, work that could’ve been used to implement new features and/or maintain existing code that’s actually in use
what the kernel is doing is the correct approach. unless they’re sure there’s someone using the thing: old, unmaintained code = bin
i tried many different algorithms at the time, but it didn’t really matter. my laptop would always, eventually, lag and get pretty hot and I would check the task manager and sure enough there were the btrfs compression proccesses hogging the cpu