Conceptually, I don't grasp how possibly exposing my PIN number at a point of sale is MORE secure. I just can't get past the idea that I'm now using the number I use to withdraw funds at an ATM at MORE places than just at my bank.
And the machine itself checks the PIN against the chip. No sending anywhere, no checking by the clerk.
You only have to trust the machine itself. If you don't, you're fucked anyway because who says a hacked machine will only charge as much as it says it will?
Card+signature is security by "something you have", Card+PIN is "something you have and something you know". That's much more secure.
A signature isn't "something you know" because it's written on the card anyway. If it's not written on the card, then using the signature doesn't do anything in the first place. And nobody checks those signatures anyway. This is why for large purchases they ask to see your ID.
If someone hacked the terminal I use for an Apple Pay transaction what exactly would happen? It's a one time token that gets passed to the terminal and I immediately get a push update about the transaction.
If a machine charged you too much, either it would say so on the receipt and you could protest immediately, or the receipt wouldn't match the charge so you could protest later. Sure, the first few customers might get fucked, but soon the bad machine would be caught. OTOH if the machine processed the current transaction correctly while sending all your codes to the bad guys, it could do so until the store noticed its bad firmware, which could take years.
Banks already correlate fraud reports to where customers have used their cards to track down offending stores that skim cards. They don't have to find the bad firmware, they just have to see "well 10 customers had their cards skimmed, and the only store they had in common was that one"
There's no way around trusting the machine itself.
I doubt it will take much for you to get past it.