Nah, here’s how it actually works.

UGC is already uploaded through the toolbox in Roblox Studio. You have to be part of the program to actually see the publishing tools for it and to have access to the publishing APIs.

The UGCValidationService mirrors the checks done on the server so the publishing tools can provide immediate feedback to the creator who is publishing their own UGC.

While they have been doing this validation already, I guess they decided to consolidate it into its own service class.