Having removed untold numbers of windshields since joining the FD back in 89 I would have to say no. First off there are any number of tools out there that do the job much better. Items like hydrolic cutters, specially made saws just for glass removal and our dept favorite... the cordless sawzall!

Using a hand saw on a windshield will cause the vehicle to rock back and forth. Whitout proper stabilazation it will require more effort and more importantly may cause more damage to the patient inside the vehicle.

On the FD the first thing we do "to" a car is "crib" the car. we stack blocks of wood under the fram and then let the air out of the tires to make the car as stable as possible. Then we try the doors or side or rear windows to gain access to the pt. About the only time we remove the front windscreen is if we are going to remove the roof for easier access.

All that being said it may have a place in a FF/EMT/Emergency responders pocket.

Hope this helps.
Be safe