Ceramics cannot be made very sharp even though many users think they are. The hard edges are very brittle and they would chip rapidly. They "can" be sharpened at home, but far less than 1% of us have the equipment to do so and the effort involved is hardly worth it. Beyond that, they are sharp enough for most kitchens, last a long time because of the hardness, and offers of free factory sharpening and other such guarantees and marketing efforts sell some knives. Other good qualities include being stainless and that they are somewhat dishwasher safe.
You'll never find one in my kitchen because the steel in my knives can be made much more sharp, I can bring back an edge any time I want in seconds, I don't have to worry much about them breaking if I drop them, and it's fun to baby them.
There is an excellent compromise distributed by a Swiss company, Kuhn Rikon
. They are Chinese made and have a teflon-like nonstick coating which comes in nine different colors. Being a breast cancer survivor, my wife prefers pink.
I don't know from which stainless steel the blades are made, but I put a 15 degree per side edge on it and it holds up quite well, at least for my wife's uses. So far they only sell a 3 3/4" paring knife but I think larger knives will soon be available because they really work. They only cost ten bucks and can be found at places like ebay, Amazon, Cutlery and More, and other Internet sources. I've even seen them at the Sur La Table checkout counter.