But can they also be driven?

This is obviously not the primary reason to get a Telsa. But a full home generator will run you $15k to buy and install where i live, and a whole bunch of hassle to install with permits. I don't have one because my power doesn't go out that much. But if i'm otherwise on the fence about a vehicle, I would absolutely want this as a feature.

In our area, when a storm hit, the roads washed out, so the generators ran out of propane. Then the local propane companies ran out of delivery truck capacity because of the demand surge. Finally, the regional distributors ran out of propane.

Our solar panels kept the fridge running, but we were heating the house with a wood stove (it was very cloudy, so we were getting maybe an hour of sun a day). If we had bidirectional house charging, we could have had warm showers + used the heat pump: We would have been able to fast-charge the car at 100-200kw in town. The house can limp through 20-30 hours on ~ 25kwh, so the charger would charge the house at a few days per hour, including losses from driving to and from town + round tripping through the battery, and also running the house heat pump.

None of the other people around here stayed online. Some propane-dependent people had no electricity for > 2 weeks (with rationing, they managed to keep their generators online for about a week, and PG&E took three weeks to fix their lines).

This was in the outskirts of Silicon Valley, so better-than-puerto-rico infrastructure, but only just.

You forgot "higher maintenance" that goes along with seldom-used things that run on gas. That gas doesn't drain itself, and if you don't do that, well, Amazon has carbs for Honda generators for $30. For something I might use once a year. No, thanks.