All VRS providers in the U.S.—including Convo—are overseen by FCC and therefore must comply by its regulations.
Under FCC policy, VRS is only eligible for deaf, hard of hearing, deafblind, or speech-disabled people, which is why the FCC requires that we go through this verification process. Your driver's license is one of the best ways to verify your residency to ensure that you are eligible to use VRS.
If you don't have a driver's license, there are alternative documents for you to submit.
You can see FCC's FAQ on this topic in ASL videos here.