Why does Roblox want us to ‘Verify’ our account with photos and government issued IDs? What are they trying to accomplish by doing this?
Probably trying to make sure people don’t evade bans, fake their age, or just data collection in case anything really bad were to happen, just guessing here though 
It was mainly done to restrict voice chat to users who actually have the required age. I did restrain from it cause I just don’t like having my personal info retrieved, but they use a third party company for the verification who claims to delete your data a few days after authentification.
According to an article posted by Roblox, they want us to verify our accounts to allow access to innovative social capabilities and age-appropriate content while also ensuring the safety of the community.