I have no experience with ZeroCater but I can tell you that providing food on any regular schedule for my 60 person company is a nightmare.

We don't want to provide catered lunch every day, but on any given day there are probably 2 different lunch meetings that order food in to try and make a meeting more bearable. Coordinating it, paying for it, ordering and all the other details are painful.

I absolutely welcome any service which aims to make this better and can actually do it.