Even heating: skillet thickness vs. electric element size I've recently started transitioning to stainless-clad aluminum-core skillets, and one oft-compared property of various offerings is the thickness - generally a thicker sandwich contains a thicker aluminum layer and thus has a greater ability to spread the heat evenly across the cooking surface.

But how much does this matter, if a skillet is placed on an electric coil element which is almost as large in diameter as the flat area one cooks on?

Anecdotally, I've noticed that a "relatively thin" (maybe 2.2mm) inexpensive Calphalon 10" skillet seems to perform fine on a 6" coil, even for high-heat tasks like searing meats.  Contrastingly, an 11" (3qt) All-Clad 3-layer saute pan of the recent "not the way they used to make them" 2.75mm or so thickness shows a definite cold region where it extends well beyond the coil to meet the vertical sidewalls.

I've recently upgraded to an almost 8" element, and am shopping for a 12" skillet which will have a cooking surface around 9" in diameter.  Given the poor performance of the large saute pan, I'm tempted to try to track down one of the few offerings that is still 3mm or more in thickness.  But given that the cooking area will barely extend beyond the coil, I wonder if it's worth nearly twice the price I'd have to pay for a 2.2mm thick one?  Granted, a 3mm pan would probably perform a lot better than a 2.2mm one if used on the 6" element.  Or going to another extreme, designs with thick aluminum and only a thin stainless lining like All-Clad MC2 would presumably have the best heat transfer, at some cost in durability.
Electric oven spirals turn on and off continuously, and the temperature of coil depends on the ratio between periods of cooling and periods of heating.

Thicker skillets act as accumulators of heat, allowing smoother transitions between those periods. They heat up slower and cool off slower, thus making temperature more consistent.

Another voice for thicker frying pan bottoms is that it prevents them from warping as much – metal contracts and expands on temperature changes. Cheap pan will warp after a while and stop forming a good contact with electric stove spiral, resulting in uneven cooking.

Hope this answers your question.