Node Painters run fully in your browser. It only store in local storage your settings and your saved sketch. Nothing is ever send to a server. It has no ads, no tracking data, no third party service. The only way I might ever know if somebody else is using it is if i ever start to pay more because hosting it would require more bandwidth.
Having a server would have made a few thing easier such as the save functionality, but then I would have to care about data safety and rgpd and a billion other stuff.
Also with ads I could maybe make money from this but right now this is much more easier for everyone.