The context here is youtube. When you're watching a youtube video on android, it's either in the youtube app, in a webview, or in the browser. The first two are not covered by ublock and the last one is the least likely to happen. (in my experience anyway)
I always use Firefox, although admittedly I don't watch that many videos. Same goes for Facebook, Twitter, etc.
There's a few apps for which I think native is important, but I'm generally happy with mobile websites. uBlock Origin really makes mobile web not suck.