A long time ago I had a cat who used to chew on poinsettias and then throw up, obviously I had no idea that they were actually toxic, she ate lots of plants and threw up, including cat grass and was a sicky cat in general. However different cats may be more or less sensitive, I would guess, so now that I know they are on the toxic list I wouldn't have them, or I would make sure they were inaccessible. I don't think they are in the same league us lilies for toxicity, but not worth the gamble.
We have one that's somehow survived for the last three years (poinsettias clearly thrive on benign neglect). We have three cats - can't say any of them have shown any interest in it but so far all good!