@hideki It has much better lossless compression than png and on functional operating systems it just werks with everything. Pngs were invented in the 90s as a FOSS competitor to gif that's hardly better than bziping raw image data
It's easy to integrate into software because it has a sane C API. It takes 1 function calls to do what takes libpng 50 lines of code
It's objectively good. Software not supporting it is a fault in the software