Good point indeed as this is something that I have left out since personally it was not too inconvenient for my situation. But lets start with managing rewards.
When I downloaded the app I was prompted to add my wallet, I linked MetaMask which was confirmed to be an applicable wallet by the community. Here is a screenshot of the rewards system how it distributes points. I have not seen this anywhere except through a telegram message by the founder, to an inquiry from a user.

I have personally not received rewards yet but it was confirmed by the community that the rewards are paid out during the first week of every month into your ETH address that you entered.
Preventing abuse is done in a similar fashion as you have stated. The app will prompt you to confirm that you are listening but in my experience it happens maybe once every 2-3 hours which in my situation is not an issue compared to the possible amount of free tokens that can be earned. The commercials are also not so bad in my opinion, fairly short and not too often unless you are trying to skip alot of music lol
I hope this clarifies some things that I left out, If you try it please let me know how you like it! Or if you didn't haha I'm new to a lot of this and perspectives help me to see a bigger picture. Thanks for bringing this up I hope you enjoy it, either way though I hope you have a blessed rest of 2020 and 21. Being involved in crypto is a really exciting and promising start :)