I know what you mean about the curious clicks on those hidden comments and posts - I myself have done that a number of times.
I also agree with your strategy and do the same thing. If somebody leaves me a thoughtful comment that adds something, I upvote it so that the commenter earns something. On spam comments, depending on the level of egregiousness, I either just ignore it or reply quickly but don't upvote.
I hope over time the majority of spammers realize they don't earn much from spamming and change their ways. I'm sure there will always be some level of spamming but will be interesting to see!