In HR times selling happy resources instead of fish will help the AI much less, as it will be able to afford huge stacks in its cities, at least on the higher levels. But it's generally a good idea to sell off excess resources for gold, as your own limiting factor is always research, whatever you do. This is one of the ways the AI can help you along passively with teching.
Huh, I had never thought about the ubiquity of HR, and the ease with which the computer could build and maintain enough troops to get all the happiness they need. I suppose at that point, you are absolutely right, health would be more useful. And there I was thinking I was so smart.