I didn't have a credit card until this year (I'm 28 years old). I've always paid cash for everything but my house which I borrowed 80% of and paid off about 18 months.
I fought the credit system and the system won. You wouldn't believe what a PITA it becomes to have no credit history.
I tried to switch power companies for a better rate, but the new company wanted a deposit because I had no credit history. I've never paid a bill late in my life, but they didn't care.
I learned I'm not getting the best insurance rates because I have no credit history.
What bothered me the most was the 2-3 times a year my debit card would get declined for no clear reason. I'd have to call the bank and learn some rule I'd never heard before about why my card was automatically declined for a purchase.
The main thing that made me get a credit card was the rewards. My wife and I spend ~$10k/month on our debit cards. We have friends that make less than 1/2 of what I do that fly 1st class, or stay in nicer rooms, for less than we sit in coach for or pay for our normal room. After looking at what we were spending, and what we could get back from a rewards card, we were "missing out" on several thousand dollars a year in rewards.
Of course, I couldn't qualify for one of the great rewards cards right away because I had no credit history. I got a Capital One $500 limit card (which my wife laughs at because it's a Platinum card) in January. I checked my credit score last month and it's up to 714. Not a great score, but maybe I'll qualify for a good rewards card in another 6 months.