What this is
A licensed off-track parlor
An OTB — off-track betting facility, sometimes a teletheater — is a licensed pari-mutuel room that simulcasts live harness and thoroughbred cards. It is not a sportsbook. You are still in the pools, usually with a teller or a self-serve machine, and the signal menu is whatever that corporation is taking that night.
Cash-and-teller culture is closer to the track than to a phone app. Age rules can differ by corporation — Nassau OTB, for example, posts 21+ at its facilities. Always read the house board.