>So "utility" is both "happiness" and "something that's useful towards the end of happiness". No. Utility is the usefulness in achieving the end. And the end is happiness. And achieving the end well is aggregating a lot of happiness. Therefore high utility is high happiness. For that reason philosophers equate utility with happiness. It's a definition specific to philosophy. Hopefully that clears things up.
You're still equating it with both the end and the means towards it. In other words, you're still not making sense.
Here's what you originally said: But now you're saying.. something different that I can't be bothered to parse right now. I give up.utility, especially for utilitarians, is not usefulness, it's happiness. It's called utility because it's useful towards the end of happiness