During the daytime, your solar panels are dumping power onto the live grid. The same grid your car at work is plugged into. And all your neighbors'. And every other car in the garage or parking lot.

During an outage, unless it's a weather-critical incident or a disaster, the convenience of not needing to go and power a generator (and thus mess with needing to refuel it, and depleting your supplies which will be more useful in a real disaster) would likely be better. If it makes sense to power up a generator, then do that. It would also be charging your car.