As a developer it’s impossible to upload .wav files directly to Roblox. Third party conversion methods must be used.
I work in .wav 95% of the time. To streamline my implementation of sound files, Roblox should accept.wav uploads, and automatically convert them into .ogg.
The .wav to .ogg conversion methods are made open-source in publicly accessible freeware (see Audacity). I understand the file size of the initial upload is hefty, but file size restrictions can be imposed.
Furthermore my DAW is not capable of directly exporting to to .ogg or .mp3 (Ableton Live). Many soundpacks for sale online come in .wav format, in my experience the vast majority. Roblox automatically converting foreign formats to .ogg would be a handy inclusion.