I do prefer buying full digital discography when available, because it’s such a good deal. For $30 or so, I get years and years of albums, while still supporting an artist with a much larger sum than I could via a streaming platform.
Admittedly, I’m still also using YT Music precisely for the reason I described above, and also because it makes it much easier to discover new music, compared to Bandcamp (something I’m hoping to potentially address in my own alternative).
I never subscribed to Spotify etc - I always bought mp3s (well, at least after they became DRM-free). It's relatively cheap. Spotify is currently charging $15/month. I can buy 11 mp3s for that amount. That's almost the amount of mp3s I buy in a year (because I've already bought most of the ones I like).
Also, when I buy it, I never have to worry about the streaming service dropping the music I like.
Discovery: Radio while driving. When I cared more about music, I would actively seek music out (checking out the charts in various countries, etc). I'm just not that into music any more.
Upload to device? I use FolderSync on Android to sync any new songs between my PC and phone. It checks daily/weekly. Given that I was already using FolderSync to sync other directories between my PC and phone, adding this directory was "free".
I'll grant simply paying Spotify a monthly fee is more convenient. For me, though, losing it all because they change their policies, lose license deals, or go under is worth the "inconvenience" several times over. I've accumulated mp3s of pretty much any song I liked ever since I understood the concept of what a "song" is. I would never want to lose that,