I had in mind that you might convince someone abstractly to support eg prediction markets because they promote truth, and then they would accept the results of such markets even if it disagreed with their intuitions. They don't have to know how to bet well in such markets to accept that they are a better truth-seeking institution. But yes, being a truth-seeker can be very different from believing that you are one.

Btw, I only just discovered the "inbox" that lets me find responses to my comments.