[stumped]

Re paying a monthly fee to stream stuff you used to own.
I had 60+GB of MP3 and 20Gb of .flac on multiple PCs I now happily pay for Spotify instead and have deleted most of its freeing up SSD space. I did upload all of for free to Google music beforehand though. Just in case.. and multiple test with my best nick convinced me that I can't hear the difference between flac and 320bit Spotify premium. I trilled qobos and tidal hi timeframe also? They all sound equally good.

I guess with video the comparison is can you tell the difference between netflix streaming at a
1080p full hd and a blu ray disc in an expensive player. I can't. Ownded discs are so inconvenient compared with rented streams

As others say, it is about convenience. It is also about having access to millions of tracks you have not bought. As retired now guitar teacher, it was great to have legit access to stuff my students liked but I would never have bought.
I note that pirate sources of music are now almost all dead. It used to be trivial to download an album but high quality legal services have won. CDs are dead and so are music torrents.

I see other services going the same way, pay to stream z never own. I just got three months of game pass for Xbox one for £1. That is a netflix style consume all you want service, and with fast internet it's great.

All very off topic for books though so I will stop now...

Though I wonder if anyone will ever do a netflix for quality ebooks, audio books, not the junk heap that is Kindle unlimited