There was a time when I was pretty much using the debit card, and another time when I was pretty much using cash. For the latter, it's pretty much the only way that my spending couldn't be tracked and I liked that element, hehe, but now I just don't care as much. Cash however is also the most disgusting and unhealthy thing that any given person handles on a day to day basis. So now I don't even use cash for $5 sandwiches, because it would mean I have to handle the cash.
CCs (properly used) can help build your credit. As for protection, I thought someone told me one of the things it has over debit cards is that the person running your info can much more easily steal the necessary info to take advantage of you with the debit card in particular, regardless of the post-situational protections? Is that right?
I wish I started using CCs earlier in life, I could have got a few free airplane tix I'm sure.
For those who prefer to buy their electronics from Costco (too bad their Panny plasma selection went from excellent to undesirable over the years), whether faxes/phones, Garmin Nuvis, Canon cameras, the Costco AMEX gives you a 3 yr warranty for free, and that's pretty nice. I think it also works on a cash back system rather than "points".
I was almost tempted enough at one point to actually pay an annual fee for the first time in my life, in order to try the AMEX Blue Cash Preferred, the cost being $75/yr. Why? Because it gives a huge whopping 6% cash back on groceries (interesting to someone who is evolving as a "foodie"). A solid 3% back on gas ain't nuthin' to complain neither. (Also 3% at dept stores.) 1% on everything else.
If I had two sons who were teenage linebackers, or that my daily commuter was a Suburban, I'd probably already have the card. If they offered the 6% back at booze stores, I'd probably already have it (I actually asked by phone if they could possibly count as "grocery" lol.)
Another really nice benefit for me about using the CC is that the filter options are so darn convenient. I have a very accurate idea about the breakdown of my monthly expenditures, whether groceries, restaurant/bar, anything, just at a click. I never had nearly the same understanding of my expenditures when using primarily a debit card or cash.
Basically, outside of an inability to handle debt, or that you didn't want any entity at all to possibly track your spending, or maybe that you prefer to engage in illegal "under the table" transactions, I do not understand why you wouldn't use a CC for just about everything.