I'd imagine they'll get some money out of it, even if it's not a huge amount, there's plenty of people who like it and think it's useful. The value to Amazon isn't what you're searching, but that you might go "Hey, that's the album I was thinking of buy", and then you're in their content ecosystem.

I don't use Unity as a daily driver but I switched it off due to the network latency and general slowness inside a VM. Aside from that I thought it was pretty decent, it'd be nice if there was more content sources but you can't win them all.