> employees implicitly would rather have 300$ of free lunches paid by the company every month than +300$ on their salary.

I know I would. It'd take the burden of thinking about what to have for lunch every day off me. When I was working in an office I'd either bring my own lunch (most of the time), decide to order (which usually required to join a group ordering from some place, or create and manage a pool), or to go out - again, where, what time, and with whom? Each of those options was a waste of time, energy and context.