First, let me apologize for the big typo in the sentence that you quoted. I forgot the but after the comma.

I think that we mean basically the same thing, but I was using a simple definition of fun from my handy Funk & Wagnalls' dictionary:

That which excites merriment; frolic; sport; amusement.

Such a definition is not necessarily consistent with eudaimonia if your definition includes long-term well being.

While the millionaire that you describe might be pursing eudaimonia, I was thinking more of a person that I knew that spent a large settlement on partying, even though with a little smart money management he would not have had to work again. After two years of partying, he was back at a job that he hated and more miserable than ever. In this case, he had a short-term profit (a two-year party), but the long-term loss of financial security and the misery that resulted from that choice.

I used the word "probably" because in my experience most people pursue short-term pleasure even if it causes them long-term pain. I have made that mistake myself. "Could" works, but it doesn't reflect my experience. So, your "fun" may or may not be profitable, depending on what your definition of fun is and the time frame you are considering.

I am advocating the long-term pursuit of eudaimonia, because even though the short-term may not be as "fun," the long term profits are worth it. Such a pursuit increases the possibilities of more fun over the length of one's life.