You can do videos as well, you don't have to get just close up pictures, and you can put photos in size perspective. In fact that is what a good training book or elearning should be doing. Not the crap that most agencies are putting out at the moment.
IMO a course like fish ID is an out of water course. And is a skill learned over a long period.
But hey why don't we just agree to disagree before you get all stressed out.
So if you are weighing a MSD with what I deem as informal/out of water courses vs classes with specific in water skills like deep, nav, drysuit, et al; I weigh those in water courses as having greater value to the skill of a diver.