This is different. This allows DJ software to utilize Apple Music as a library. You would still need DJ software to actually make a mix.
However, for your use case, if you're already using Apple Music, you can set start and end points on individual tracks (Get Info on the track, Options). This is nondestructive, but not specific to the playlist so you'd have to turn it off again to hear the full track, and your export options are limited to burning to CDs.
Am I reading right, a new product has only 'burn to CD' as a way to listen offline? Haven't had a CD player in the house for a decade or more. Why not just cut a wax cylinder?
It's not a new product. The functionality I'm talking about dates from when Apple Music was iTunes.
You can listen to the playlist offline just fine. I just mean you can't export a playlist of trimmed tracks as audio (e.g. "My Mixtape.m4a") from within Apple Music. If you sometimes want to hear the full track and sometimes want to hear the trimmed tracks as a mixtape, then it's not a good solution. But if you just want to cut a 5 minute intro or 20 minutes of "hidden track" silence then it's there.
However, for your use case, if you're already using Apple Music, you can set start and end points on individual tracks (Get Info on the track, Options). This is nondestructive, but not specific to the playlist so you'd have to turn it off again to hear the full track, and your export options are limited to burning to CDs.