YSK long noise videos cant effectively be compressed and as such take quite a lot of storage space and bandwidth. So if you want to keep the hosting costs of social media platforms low, for example when going public, you definetly wouldnt want disenfranchised users to upload them to your platform. This is the kind of noise you would want to avoid: https://stackoverflow.com/questions/15792105/simulating-tv-noise#15795112
It’s likely that the compression uses a fixed bit rate, meaning that no matter how large the original file is, the file spat out by reddits compressor won’t be any larger than any other video of the same length. The quality of a video with higher entropy (like a noise video) would simply be decreased until it fit into the allocated space. That means this wouldn’t work.
If it’s VBR, either two things can happen, the compression esteems the noise can be averaged to a solid gray background, and the bit rate will be very low to just display a solid gray card, or it deems each pixel worthy of staying distinct, which forces the compression to drop and will raise the bit rate to the maximum.
Oh yeah good point, I didn’t think about server side compression. But I think noise videos might still be worse, since they provide no additional content for the platform.