Digital menu boards

Hi, I'm doing a small research on how effective the usage of digital boards at restos/cafes. 
are they good in terms of client's comfort and increase in sales?

There is actually quite some fun psychological stuff going on with these digital order boards.
Haven't worked with them personally, but did review them in my master's consumer psychology course.

Consumer are more likely to order more (more unhealthy) foods because they don't feel the pressure from explaining their order to an actual person.
(less social pressure to order correctly)

You can also service more customers with less personnel taking orders.

However it will all depend on the type of restaurant that you are running whether or not it is a positive fit. I can imagine that it doesn't fit into a mom and pop shop.
I don't know how much the maintenance of these systems costs, or whether or not it will actually increase sales.

Thank you, exactly, in terms of psychology it's more convenient for shy people, for example, I don't know as for popshops either, but as for moms it's suitable. I remember my kid clicking the board and ordering everything he wanted)))))I barely had time to stop him.