As you say, the software is completely usable in its current state. I'm using it for my game projects without any issue, and the results are amazing!
Don't feel bad in any way. Ultimately, you don't owe people anything and the price for the software, even in its current state, is still great value. Of course I'd love to see more stability, bug fixes, improved usability, and new features, but it's much better to know that the developer is happy in life.
It would definitely be nice to see an open source version, or at the very least an option to download the project files so that the community can make tweaks to functionality and build their own version, and even submit for review. There are a few features (like masks) where it's clear that a bit of extra work would turn it from usable to great.
Either way, thanks for the awesome software, and I'll share my games on the page when they're done 😎