You don't get a choice on what you use, the health care providers do. STARS is activated to scene responses in conjuction with ground personnel, or more often they are activated BY the ground personnel, and they can't fly in shitty weather. Most high performance EMS systems have protocols to stage a helicopter, but it is not put airborne until the ground crew makes the call. The only change to this would be in environments where ground crews can't access the patient. Even more often it occurs where the ground crew gets to the patient, transports them, and has them at the community hospital before the air crew can even get there. The air crew than transports from the community hospital to the higher level of care hospital (usually a level one trauma center).

In short, air transport will NEVER replace an effective ground system! So, pay those taxes and enjoy!