I'm a very happy Apple Music subscriber, but I'm also 52 and so own thousands of CDs and hundreds of LPs.
I subscribed to AM for a possibly non-intuitive reason: for me, the "all you can eat" aspect is secondary. The driver was "stop syncing my phone." My library is too large to carry on my main computer, so the "music computer" had to be the one running iTunes and whatnot. Getting something new on there was a hassle, and couldn't be done on the move.
Moreover, while this scenario made sense to ME, my wife found it so off-putting that I discovered she was just not listening to music on her phone at all.
AM solved this problem pretty well. PLUS, AM has a feature where it will give you access via Apple Music to weird, indie, or out of print stuff in your library that might not exist in Apple Music's library.
A case in point is the 1990 Wendy & Lisa record Eroica. It's one of my favorites, and has always been part of my library -- it's even been re-ripped, because the first time I digitized it I only used 128Kbps MP3, and I wanted it at 256Kbps AAC. But it's also 100% not available via any streaming service because of rights issues of some kind.
YOU can't get it from Apple Music, but I can because Apple Music sees it in the library on my music server. That's pretty cool.