They started as a ridiculous way to stand out, transitioned on to basically self-parody, then once the novelty wore off everyone just went "huh, why not use a sentence as a title?"
Once it stopped being weird it turned out that shoving a short description of your story into the title is a good way to grab readers.
Once it stopped being weird it turned out that shoving a short description of your story into the title is a good way to grab readers.