So with Apple can you upload songs to "your" space on Apple and play them through your car sound system when you drive? Like if you have some obscure album I'll use "American Noise", a local Cleveland band from the 80s, and Apple doesn't have it (Amazon doesn't either) in their inventory, can you put it there in Mark's Space?
Yes. I forgot to mention that.
I have all my own music (i.e., music I have made) on my Mac, in my music library. This is sync'd to Apple's cloud, so I can access all that stuff from anywhere. If I'm driving along and I want to hear an old recording I made, I push the button on the steering column and ask Siri to play whatever by moi, and she does.
Also, if I have an old MP3 I ripped from a commercial CD, and I sync that to Apple, and Apple has a higher quality version, it will stream me its better version.
I hate to sound like a fanboi but it really is a life-changing experience.