I mostly use it to make mp3s. Downie’s default postprocessing is set to mp3. Hazel watches the output and sweeps it into the podcast sideloads folder. If I want to watch the actual video, I switch the post-processing type to mp4 while the download is in progress.
Channel subscriptions are in RSS (readers discover the feed URL when you paste in the channel page.) I just copy the URL from the RSS client and paste into Downie. Then I mark as read after getting what I actually want to hear or watch, so revisiting isn’t an issue.
There’s another nut I’d like to crack, which is using this approach to build a library of conversations and documented experiences. Part of replacing Youtube is replacing it as the place you go to see or hear something you’ve heard before. The metadata on Youtube is so poor and I hate how it trains us to hunt until a familiar thumbnail and title jumps at us. I It’d be something similar to the (hopefully) eventual answer to @beck 's unanswered question from a few days ago.