Such a bot would be very useful for a particular community to have. Provided that bot is not the only means for assigning rewards within the community then it's false-positives will not be so bad. Particularly if the bot kept on learning what the community liked.
Where I to produce a user interface for steem - this would be my point of difference. That there was AIs that learned what individuals would probably like to see. You can do that off very broad metrics and by observing user behaviour. But, this is an AI at the level of the tools and it acts as an assistant to users.
However, if the bot had way too much SP then it becomes economically attractive for bad actors to learn how to fool the bot. So, yeah, I'd rather tune the bot to learn individual preferences to get around that.