Wordpress updates and gutenberg bloat have created constant bugs over the past few years. The idea is a headless CMS that feels like wp with familiar workflows and end-points. It's easily usable by the massive user base of wp without all of the excess. I have about 15 years of experience building with wordpress, and I felt that it was time to take this in a better direction. As for sustainability, it will be a lot simpler to maintain compared to wp because I'm not adding bloat for the sake of it and will simply need to keep it compatible with newer version of PHP etc. Please let me know if you find any bugs. :)