A:
It is just another method to start the flame. The old style "standing pilot" has now been forced out by greenies and code as it burned a bit if gas all the time, generally in the later designs, by holding the "pilot valve" open. The standing pilot system in a way it is less desirable safety wise - if - if something were to fall like a kitchen towel on the range top (as it applies to a cook top), it might accidently fall in just the right way to start something. Also, gas is being wasted (an immesurable amount yes) and the pilot vale could malfunction letting that tiny bit of gas fill the room (maybe depending on how leaky the room is).
What an electronic ignition is - is an alternate method to light gas to a standing pilot. It either sparks - the pop-pop-pop sound (like a sparkplug in a car) - or - uses a resistive heating element (like the glowplugs in a diesel engine). Perhaps the biggest diference is that electronic ignition is a 'start on demand' system vs an 'at the ready' system like a standing pilot (light).