There are Taser models that offer multi-shot capability ('X2' model) and those which can be used as contact Tasers in the event the shot misses.
In self-defense training with firearms, a good instructor will teach students that there's a 21-foot distance where use of deadly force is prescribed because handgun bullets -- like medicine -- often need time to take effect. An assailant armed with a knife can take several shots to critical organs, cover the distance of 21 feet in an eyeblink, and still carve up a pistol-armed defender like a Thanksgiving turkey before finally expiring -- even if he's still getting shot repeatedly.
In that situation, a Taser is actually more effective than a pistol-caliber handgun. You get a solid hit with a Taser, and you're going to the ground for awhile unable to do very much except make little squeaking noises. Comparatively, a pistol shot must strike a vital organ or the nervous system to achieve a 'stop' on a hostile target, whereas a solid Taser hit can pretty much end the fight right there from a pretty long distance distance even if the Taser projectile strikes the subject an area where a handgun bullet wouldn't achieve any suitable effect.
They're two different defensive means that only share some similarities.
Now if you want to continue to play 'What If?', maybe we ought to wait for an ancient Spartan hoplite to come in here and post that the nine foot long bronze spear beats absolutely every other weapon in the world at short distance when properly employed.
The 21 foot rule does not works as well if it is dark or there are obstacles.
I’m not playing “what if”. I was just responding to those lame brain talking heads who are saying “What if Zimmerman had stayed in the car” or “What if Zimmerman had said ‘the cops are calling. Do you mind waiting?’”
I did learn something. In all those horror movies where some vampire reaches into a man’s chest and pulls his heart out and he stands there for a few seconds looking at his own still pumping heart, it’s actually possible.