Better to protect yourself by registering it under creative commons or a similar licence.
It seems to me that the bands or musicians should distribute their music via their own websites. I think that then the users would care much more.
Instead of paying to download music, the users "pays" by following you across social media / streaming services. Granted it's mostly used for copyright-violating edits, but some musicians use it for original tracks too.
It's how basically any electronic music producer makes a name for himself before they ever sign a contract with a label.
What should be gated and limited is the commercial use: reselling, relicensing, using for business, etc.
> the optional payment (I promise you nobody's gonna do that)
Such "promises" seem to be based on no facts. Moreover, they contradict my personal experience.
I would be very interested in using that business model. In fact, I have already used it with other types of services. I have paid for software that is open source, free to download and free to use. Multiple times. Simply because I like the software and I wanted to thank the authors for it in some tangible way.