MJPEG is just a very simple "video" format that needs very simple and cheap electronics to work. Video encoding blocks are mostly part of bigger SoCs and comes

MJPEG is just a very simple "video" format that needs very simple and cheap electronics to work. Video encoding blocks are mostly part of bigger SoCs and comes with licensing costs. Same goes on the other hand for the receiving end - decoding a stream of JPEGs is just much simpler in both CPU use and code complexity than dealing with something like H.264.