I'm thinking that adding enzymes to the diet of a pet that has eaten processed food in the past, might not be a bad thing. If the pet has always been fed a raw diet, then perhaps it isn't necessary. But for those that aren't fortunate enough to have always eaten raw, who knows what kind of damage, even minimal, may have been done, or what benefit the enzymes can provide?
Ingested enzymes are denatured in the stomach, so they aren't making it to the small intestine and hence cannot be helping with actual digestion. Many veterinary discussions of this subject stop right there. Enzymes are not getting past the stomach, so the whole idea must be faulty.
However, in humans at least, enzymes do work in the mouth (they are released in saliva) and stomach, not just the small intestine. I'm not sure we know enough about cats and dogs to say that is, or isn't, also the case for them.
Just my
.