I think the point was that it defeats the common purpose of using anonymity software if you are submitting identifying information (your car registration inform

I think the point was that it defeats the common purpose of using anonymity software if you are submitting identifying information (your car registration information) through it. It doesn't necessarily have long term consequences—you can generate a new identity—but it nullifies that session's anonymity. However, that doesn't mean there isn't a good reason to use it anyway to make a statement and promote legitimate usage of Tor.