Comment by marginalia_nu

You can have other formats as well, and the one you describe can work out, though you're at serious risk of losing the audience before the big payoff.

I think what matters the most is that the reader can tell quickly whether the text is interesting.

You could start by e.g. describing a mystery, and then proceed to reveal the truth later, this sometimes works, though if the payoff isn't there, readers will feel cheated.