I've occasionally thought about getting vanity plates for my Model 3 when I get it sometime before the end of this decade... but have similar reservations as others have expressed here, namely why do I want to draw even more attention to the car, and often vanity plates just make you look like a complete wanker unless they are particularly creative.
One thing that I find truly idiotic are vanity plates that repeat what is already badged on the car. I'm sorry, but when people pay $400 a year for that, it's the stupid tax. "FORD" on a Ford. Yes we know it's a Ford, it has a badge on it saying so. "928S" on a Porsche. No *sugar*, Einstein, it says that too on the badge.
So as great a Tesla is, "TESLA" on a Tesla is just a waste of money, as is "P90D" and similar when it already says that in silver letters just up a bit and to the right.
No doubt I'll annoy a lot of people with such rude commentary. Thumbs down and all. Each to their own, eh.