yeah, same here. and I got a lot of free stuff because of my miles using my credit cards, last one I received is a baby luggage it's trunki tigger so cute!
I use a debit card, as well as a credit card.. however I don't use them as "credit" I just use them as a form of payment.. and clear them at the end of each month.
We use credits cards however we pay them back before interest build up occurs. Just to build company credit. There are also great incentives for using credit versus cash or debit.
Many people use credit cards for the perks. Some cards offer a cash back reward for every dollar you spend - American Express Blue, and Charles Schwab both offer this incentive. For Schwab it's a flat 1% back on everything. American Express has different tiers, with the highest being 5% back on gas and groceries, and 1.5% back on everything else. Credit cards also offer safety that debit cards do not - if you have a problem with a vendor, you can dispute the charge. With a debit card, the money is gone as soon as you make the transaction. Be careful.