Our dog loves carrots. I can see number of ways in which these are good for him and since a vet concurs, I don't think we are dreadful people.
Mastiffs will truly eat nearly anything. I keep him away from most fruit, as grapes (and raisins) are poisonous to dogs. He eats a bite or two of grass in the yard.
But when he is fed, twice a day, it's meat.
When they are puppies, they will eat gravel/small rocks, so you have to watch out for that.
Honestly, this was a joke, at least it started out that way. When did we get so serious about the diet of dogs? As I said, he likes cheap burgers. Once a month or so, he gets them for treats.
Some dogs can be partial to some veggies and even fruit, but to put a carnivorous animal on an exclusively vegan diet disregarding genetics, millenia of meat and carrion consumption and the dog’s health is a fairly vainglorious act in an ignorant albeit well meaning for a contemporary personal set of social mores.
“Oh, my dog’s a vegan, isn’t that so cool”.