Is it true Americans do not use bank debit cards in retail and for online banking?

I am from Amsterdam Netherlands. We all use bank debit cards with PIN code all the time for shopping in retail and making transfers online (using little authentication devices). I have the notion that Americans do not use bank debit cards at all. Just credit cards.

1.) Is this true?
2.) Why is this? The cost of credit card transactions is much higher..?
3.) What is the point of using credit with interest if you have money in the bank?

Thanks in advance for your insights!