True, but if the same un educated hands, are on that snaffle, versus some advanced curb, then the possibility of damage is greater with those hands on a leverage bit
Ditto, if even you have very good hands, and place a spade in the mouth of a colt, versus in the mouth of ahorse that has gone through that entire vaquero program of creating a Spade bit horse, you are going to do damage, as that colt has an un educated mouth, and thus does not know hoe to respond to that slight signal
It is also, why I read somewhere, that Ed Correll spoke about creating a Spade bit horse, stated that when a vaquero rode out to work cattle, on a horse up in a Spade, he would often pack a snaffle, tied on the back of his saddle, in case he had to school that horse
Bits are graded, in tack catalogs and elsewhere, as to how 'strong they are, or as to what level of horse they are suited for. This grading would be impossible, if you had two variables-ie bit design and hands on the reins.