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 WAV?
WAV is raw PCM audio with a small header - uncompressed, unprocessed and enormous, at roughly ten megabytes a minute for CD-quality stereo. It is the working format of audio editing, sampling and speech tooling, where every stage wants the samples themselves rather than a codec's approximation.