Less mass will yield longer range. I know you're referring to the battery accounting for a large percentage of the weight, but a smaller vehicle will get the same range with a smaller battery, and the weight savings compound. If the vehicle weighs less, then all the components supporting that weight can weigh less as well. Unsprung mass can be reduced significantly. Acceleration, braking, handling, and top speed all improve as a result. Components will also generally cost less, reducing the price of the vehicle and making it cheaper to maintain.

Interesting, yeah, my instinct is that the sensor weight delta would be negligible but perhaps not.

Fair enough, I guess I'm speaking too generally.