I've worked around the restaurant industry for 10+ years and am a founder of Ordr.in, part of 500S' food portfolio. Digital ordering absolutely increases profitability. Average tickets are higher (estimates are 15-20% higher) and cost of serving the order reduced. Plus online orders smooth out and extend demand. I.e. serve more customers without adding fixed cost. Restaurants are just beginning to adopt online and digital tabletop ordering. Not only is online ordering profitable (though I don't think there is a one-size-fits-all solution) but customers are demanding it. This year 40% of diners will order online at least once (up from 13% 5 years ago). If merchants don't lead, customers will.
