PayByFace provides merchants with a service that combines digital signage with facial biometric-based payments. The company integrates its middleware platform with off-the-shelf tablets merchants use as point-of-sale terminals. Merchants don’t pay a fee to use PayByFace facial authentication on their tablets. The key to PayByFace’s revenue model is the advertisements presented on those same tablets, which can run 10-second ads on a continuous loop as well as 30-second videos (without sound). Merchants can select pop-up ads to present when a purchase is being made, whether secured by the...