Generic Comments Fail for a Structural Reason
The problem with pool comments is not that they are short or enthusiastic — plenty of real comments are both. The problem is that they are interchangeable. A comment that would fit equally well under a recipe video, a gym selfie and a product launch is a comment that says nothing about any of them.
Your readers notice this faster than you might expect. Someone deciding whether to trust an account scans the comment section, and a wall of context-free praise reads as bought within about two seconds. That is worse than having no comments at all, because a post with three real comments looks small while a post with fifty fake ones looks dishonest.
There is also a practical downside: generic comments do not invite replies. Nobody responds to "great post". They do respond to a specific question or a comment that takes a position, which is how a comment section turns into an actual conversation.