Well, we may call this a kind of bet on the odds of probability. It is basically a side bet and happens when the dealer's face-up is an ace. In this case, a player has an option of 'taking insurance' so to speak, before the dealer checks the card in the hole.
I have heard people say that this bet (as is with all side-bets) highly favors the house and so most experienced players do not like using it (leaving it mostly to the novices and the faint-hearted).