No no no, you're not getting it.
Of course you won't download every decal and face on their hard drive, just ones they're currently wearing.
I do get it, but if you connect to a server where a bunch of people are using custom decals, you have to download all of the custom decals currently being used, thus adding some unnecessary amount of time to the load screen, then once you do spawn, it becomes moot because anyone that connects after you, you aren't able to download their custom decals unless there's a way to change it so you can download them while you're in the server
I'm not saying it's a bad idea, it'd be neat to have something like this, but it's just that with the current ways to see it working just make it seem unnecessary and a pain unless there ultimately is a better way to handle seeing custom decals