No PINs for credit cards in the US.

We don't need to enter the PIN for most of the credit cards or debit cards in India, but we do have to sign it. Although it's just a formality. Usually when we split the bill, one of us signs all the receipts. :)

Now that being said, we get an SMS on every transaction, and for online transfers, we have two factor authentication using the mobile phone. We can call the bank any time to report a stolen card and would be covered for a fair amount of money depending on the account, as long as you report it within 24 hours as I remember.

Not for coffee-sized amounts at major coffee chains, no.

Debit cards require a pin, but credit card transactions less than some amount(I think it is $10) don't require anything other than the swipe.

Many debit cards can be processed as credit cards and then don't require a pin. My bank actually encourages using the debit card as a credit card by offering more points per purchase when you do it.

What? Perhaps if you have down syndrome, but otherwise takes around 5 seconds. Swipe card, enter 4 digit pin, press enter. Faster than it would take the cashier to type in the amount you just gave him, much less make change.

Down Syndrome? Really?

In any case, plenty of people do struggle with it- the old especially. But that's not the biggest factor. With a swipe everything is done by one person- the cashier. PIN entry requires a back and forth between customer and cashier, and I've seen plenty of cashiers not notice that the PIN entry has gone through, etc.