People wanting enjoy themselves in a mature environment without the fear of having a bad influence on minors, like during raves and weekend parties.
+18 Content extension with ID verification via an outsourced company like veriff
The mature content extension can also be paid to cover the costs of the verification process.
A feature like that would greatly enhance the experience of VRChat as a hosting platform for the ever-growing club and party scene of VRC and other 18+ communities.
(But please also keep in mind that there needs to be an option for shared event host accounts)