it's not so much heresy as foolishness, take that lightly. It's just that every cook that I ever worked with that had a ceramic knife would show it to me and it had a busted tip and was dull. they are brittle and apparently difficult to sharpen once they become dull, although I am no expert.
I can't think of too many things I'd use/want a ceramic blade. Maybe on my mandoline? Would be nice to buy some ceramic blades in a 10-pack or something, just for mandoline blade replacements? I sharpen steel blade with 2000-grit sandpaper at the moment, seems to work well.
How about a ceramic slicer for lettuce? Kind of a waste of a knife slot I suppose.
Peelers are cheap, don't see where that could be cost justified.
ooh.... How about a ceramic pasta cutter? A set of ceramic ring cutters? (Can you do that?)
HAHAHA, How about a ceramic Maguro Bocho? Sweet!