Snagit, (1) though it has free trials, is, at a technical level “high end” and (2) the vast majority of people (a) do not know about Snagit and (b) are not going to go looking for it. Thus, in most cases, a water-marked image is not author/creator compromised, the number of cases it is compromised will be reduced, and the total cost of legal remediation resolving the much fewer CIVIL cases makes pursuing them more likely.
Creators/authors KNOW their ownership WILL BE compromised. The main thing is to reduce that. They can do that with technology, they don’t need new laws making criminals.
Well, watermarks are a whole other thing.
Snagit or screengrabs will get the water mark, too. But you knew I knew that, right? :-)