WAV is a simple file format that was created in 1991 for people to use with Windows 3.1. This file takes the audio signal and converts it to binary data using an analog to digital converter, which essentially takes snapshots pieces thousands of times each second. To put this into perspective, the typical CD audio will record at 44.1 kHz, which translates to 44,100 of these slices each second. The audio frequency can be up to between 20 Hz and 20 kHz. There are a lot of advantages and uses for this older format today.
Firstly and probably most importantly, it has a lossless and accurate format to it, which means that you will not lose any audio quality in your recording. It is also a basic format, which makes mixing the music a lot easier. You will also get a more dynamic range with WAV. There are some downsides with this. WAV files are quite large, which makes them less desirable for streaming.