What you have been hearing is people talking about the alternative dining options that are pretty much commonplace on cruise ships these days. Most cruise lines now have "upscale" restaurants on their ships, where you can eat for an extra fee. These restaurants offer better cuts of beef, specialty seafood, Italian cuisine, etc. These places are akin to dining in a big time restaurant in NYC. A typical fee is $20 per person. On RCCL ships, they also have Johnny Rockets with a $3.95 per person fee.
One can also find charges for specialty coffees and pastries at the cruise ship equivalent of a Starbucks. And you will find extra-fee ice cream on some cruise lines. RCCL has Ben and Jerry's stores on some ships, and Princess has Haagen-Dazs.
All main dining room food, buffet food, and room service is included in your cruise price. With the exception of Johnny Rockets on Royal Caribbean, I've not gone to the extra-fee restaurants and I've not felt deprived nor hungry!