No need to buy a cabbage if there are leaves on a cauli, that's why I think they cut them off.
Theres certainly nothing wrong with them, quite delicious as far as I can remember. I've eaten plenty when you could get them, never see them nowadays which is a shame.
I cook all but the most toughened ones, delicious IMO
The thick stalk when chopped fairly fine is lovely in stir fries too. Not much waste to a cauliflower here.