people recode pr0n ? now iv'e heard everything.
i used to have to tinker with some tv captures of really-fast-moving-action sporting events due to the broadcaster badly limiting bandwidth and making it much too blocky.
nowadays they've got enough better so I just leave it as-broadcast, like you propose. "good enough" for home viewing which is usually once in a blue moon.
having said that, occasional mpeg2 SD type captures get put through the filter/nvenc mill, and it's still "good enough" for rare home viewing.
depends if you're a video buff I suppose, in which case you will do what your needs tell you to do
good luck with buying disk space, you must be rich !