What, exactly, do you get for your $10.99 Apple Music subscription? I don't see any benefit now that I have it.

If you want to do what you've been doing, you don't need to subscribe to Apple Music.

You can continue to purchase iTunes music without subscribing. See: Buy music from the iTunes Store - Apple Support

There is an Apple article that explains how to cancel subscriptions. Click on the following link: If you want to cancel a subscription from Apple - Apple Support or you can use an internet browser to cancel as described in How to cancel Apple Music - Apple Support

You can stream over 100 million songs ad free. See: Apple Music - Apple