Or your menu! Even in the age of delivery apps people still keep around takeaway menus.
If you can't fit your entire menu on one tri-folded sheet of letter-sized paper [with readable print size], it's time to do a statistical analysis on your orders, and cut all the dishes that don't get ordered enough to recoup the costs of offering them. Move them to the infrequent specials menu, if you really can't stand to never make them again.
If I recall correctly, one of the major reasons single-location restaurants fail is menu bloat. Diners take longer to decide what they want. It's harder to identify the dishes that are least profitable. Prep is more complicated. The order management system might require additional button presses to navigate between pages.
And put the restaurant equivalent of keyboard shortcuts on the menu. As a customer, I like being able to order by number, particularly by single-digit numbers (or single letters). "Give me a number one, a number four, and a number eight, hold the mayo."
That may or may not apply to those restaurants, but a restaurant can't be everything to everybody. They might do better by not trying.
Consider this applied to tech companies: you need to make very different decisions if you want to start a free social media site versus a webapp aimed at businesses.
What about the trees?
Just because you ordered food and didn't cook at home doesn't imply you don't care about the environment. Perhaps you cook at home most days but on this particular day you were going to get home from work late and still needed to have dinner ready for your family. You still want the food delivery to be as environmentally friendly as possible. Thus I eschew being given paper plates, styrofoam containers, etc when I order out (as I can simply use my reusable ones at home with that food).
Whether you care about trees or not, the environmental impact of a paper menu (especially if it’s just a regular piece of office paper, rather than a glossy magazine-style page) is negligible compared to the rest of a delivered meal (well under 1/1000 of the total).