ok so the problem for the money launderer is that as spotify gets better at detecting bots and spam accounts they will have to pay increasing amounts of dirty money to get out clean money, at what point does it become a losing proposition to them, that is to say when this form of money laundering is less efficient than older forms?
A bigger problem would be that Spotify pays very little. And to have the bot "listen" to a song (to be eligible for payment) takes minutes of streaming, which turns to tons of time and a big bandwidth bill, since they'll need to do thousands of them in parallel...
it's obviously worthwhile for them now to do this, but sure it is an additional cost that at some point will make it not worth doing.
This is where malware run bots come into picture ... it solves a lot of problem like not having to pay for bandwidth, evading detection by distributing access to the songs among varied IP and geography, etc.
They wouldn't have to actually play the songs, could just use the offline listening reporting endpoints.