Even if carbon reduction were the only reason to buy the car, this would probably still make sense. If you're able to use it nearly 100% as an EV (which most people can do), and your home energy is renewable, then you're going to reduce your carbon footprint.

But the reality is that most people are buying it for convenience and/or novelty, not reducing carbon.

I own one and am fully aware that the car can't become carbon negative until well into its lifespan just because of the carbon required to produce its battery. The most eco-friendly purchase for us would've been... not buying a car at all.