This is exactly what you need for the intermediate stages of a video game asset pipeline where you have a prepared set of images ready to be re-encoded to compr

This is exactly what you need for the intermediate stages of a video game asset pipeline where you have a prepared set of images ready to be re-encoded to compressed and packed textures: you don't want the overhead of decoding PNG at that stage, neither do you want a text parse like PPM. Bytes that can be used directly are good. It's a hugely uninteresting format in most respects.