What is OGG?
Ogg Vorbis is the patent-free lossy format that came out of the free software world. It compresses well and it has always been unencumbered, which is why games, Wikipedia and open-source projects reach for it while consumer hardware mostly ignores it.
What is MP3?
MP3 is the format that made digital music portable, and thirty years on it is still the safest bet that a file will simply play - on any device, in any car, in any decade-old piece of hardware. It is lossy, and its patents expired in 2017.