It really depends on how they define their mileage rating. If it is an inflated number like some EV manufacturers, then yeah. If it is a conservative rating, then it's a useful amount of range for an "in town" vehicle.
It's not about "inflating" it. It's more that the energy needed to move your car a certain distance is quadratically related to the speed, due to aerodynamic drag.
Efficient vehicles spend less energy on other stuff besides moving the car (e.g. by having heat pumps, induction motors that can be turned off without any drag, etc), so tests conducted at a lower speed will appear to have a better range than tests at a higher speed. Meanwhile, less efficient vehicles that waste energy at low speeds will appear to have more similar range at both low and high speeds.