Why would anyone need a "cooler" for ice fishing? A plastic grocery bag works fine. You certainly don't need to keep drinks cold with all the ice your sitting on, just saying.
You are EXACTLY correct. Any can of beer placed anywhere on the ice will grow cool - no need for a cooler.
BUT, this is discovery of an amazing feature and all it takes is to rename the product.
It is now the amazing Dipstick Can WARMER - your beer will never freeze again.
Harness the BTUs hidden in the cold lake water to prevent your beer from freezing.
Never drink a beer slush again. Killer feature for people who fish all day in sub-zero temps with no shanty to keep their beer from freezing.
Now we finally have it right!