The cost to take a menu and print it for each table plus some is non-zero. The cost to replace the old online menu with the new menu online is near-zero, besides man hours for the manager/chef to determine the seasonal cuisine.
Cost for paper menus is nominal, and lasts thousands of eaters. Disagree cost to replace old menu is near-zero, most restaurant owners have to hire a dev for edits. On menus you just use a marker
The restaurant could lose out on sales from customers who are dissatisfied with a lack of a physical menu, especially many older people who are not as comfortable using technology or don't even have a data plan.
The restaurant could also lose customers who are tourists, who don't necessarily have a data plan while traveling. While it's a bit more convenient for the restaurant, the convenience comes at the cost of the customer.
Also, the UX for many of the menus is often pretty bad (with diners often asking: "how do I place an order?" "did I place an order or not?" "how do I go back?").
If the restaurant offers great dishes that cost near-zero, I would find that approach acceptable as a customer. If they want far-from-zero money, I would look elsewhere.
