I'd imagine most of that is out of annoyance of dealing with pirate version or just them finally being able to afford it as it is now part of their job.

I feel like easiest way to monetize apps like that would be free noncommercial license. Want to DJ your school party ? Go ahead, as long as nobody pays you it's fine, and if someone does, well, now you have money for license.

You're also building potential user base, when everyone can play with your software without limits many will pick it when they will do something commercial