This is correct.
Heat treatment of animal food has benefits, like killing parasites, softening meat enough for weak human teeth, extracting proteins from bones through boiling, or denaturating harmful proteins, like those from egg whites, but it has little importance for digestibility.
In general, heat treatment is not useful for fatty substances and it is seldom useful for proteins. Heat treatment is important mainly for making starch digestible and for releasing various components of vegetable cells that would otherwise require much more chewing or much more fermentation time in the guts than possible for humans.