Nut flush on turn when you think full house made? Why Raise?

[arfsananto]

But it is also an hour's work to make up if you lose...
Could the answer here be in a difference in goals/playing styles?
My inclination here would have been to play this hand just as Hero did. My playing goal is to win as much as possible, but with as little variance as possible. I know that I am not as aggressive as most here, but that is by choice. Many want to push every edge, pick up every possible bet. But I think that also necessarily leads to higher variance.
My goal is to play a game which is, first, winning; then, with daily results as close to expected long-term results as possible. I would rather have smaller winning sessions in exchange for fewer/smaller losing sessions.