That is an interesting article for sure and I get that more engagement is intuitively a good thing. But I believe the author takes for granted that because of their higher engagement, Apple Music is better business than Spotify and that is not necessarily true.
Personally, I have tried both and the experience I got from Apple Music was always much better, even when they first launched and the app was a little confusing (and I remember this was widely criticised at the time).
Additionally, Apple offers something that, to the best of my knowledge, none of the other streaming services offer: on iTunes, you can build your library by combining streaming as well as files. Roon has this as well, of course, but I don’t believe Tidal, Spotify or Qobuz give you that functionality (I could be wrong, I haven’t tried Spotify in a while and I’m just starting to try Qobuz).