This is true when loading directly off disk, but in VRChat’s case everything we use gets compressed into AssetBundles, which have their own (much tighter, lossless) compression method. The load-time improvement discussed there is just ‘it loads from the disk faster’, which is true regardless of compression method, as long as the ratio is the same. Putting the AssetBundle compression on top of Crunch just adds another layer of work to get to the end data, and compression methods don’t usually stack well - you gain very little from zipping a 7z.
That being said, there is some potential uses! There is some situations where you’d want explicitly lossy texture compression to make your download size more manageable. So we’ve left the option open - it’s just not applicable to the general case.