YouTube probably has the best catalogue of electronic music too, but since they removed the 256Kbps AAC format, we're stuck with the audibly lousy, frequency-limited 128Kbps crap. Well, it was good till it lasted.
They're probably getting mp3 streams I would imagine. Definitely not transparent at 128 kbps. I'm not sure who Youtube streams Opus to, I should look into that.
Yes, I'm actually quite impressed that they offer opus @160k. The real issue with Youtube is that you never know what the source was. If they're reencoding that from a 128 kbps mp3, that suddenly becomes much less impressive.
Things youtube don't have (I am french and I know that a lot of french punk/rock/metal I like is not easily found) Spotify is unlikely to have either.