The focus thing is real, having a second app open while trying to practice something just splits your attention constantly. Having the video as a local file means you can pause, rewind, and loop specific sections way more easily too.
TikTok Downloader grabs the clip clean so it plays on any video player without needing the app at all. I use it for woodworking tutorials mostly, set the video in a corner of my screen and just work through each step at my own pace. No autoplay sending you to something random mid-project either. Once it is saved it is completely yours to use whenever