My guess: When evaluating evidence, human brain tends to conflate what /is/ true with what we would /want/ to be true—e.g. whether the evidence makes us happy or sad. The equivalent bet takes the “want” focus out of the equation, instead focusing the “want” on picking the best bet—therefore changing it from a noise that stands in a way of accurate estimation into a tool that encourages it.
My guess: When evaluating evidence, human brain tends to conflate what /is/ true with what we would /want/ to be true—e.g. whether the evidence makes us happy or sad. The equivalent bet takes the “want” focus out of the equation, instead focusing the “want” on picking the best bet—therefore changing it from a noise that stands in a way of accurate estimation into a tool that encourages it.