JPEG is like 50x more complex than PPM, but we eventually moved off that standard as well due to storage size and feature limitations. Plus, it's being adopted by both iPhone and Android--it's not like it's a proprietary format specific only to Apple.
Not to mention HEIF/HEIC images take up a fraction of the space of equivalent quality JPEGs, which is significant if you're a shutterbug who fills up their phone with photos.