Often1

Any company which is paying its people, both the traveler and an accounts payable type, to total up coffee receipts is crazy.

With the exception of people who have client entertainment responsibilities, per diem based on location makes sense. Who cares whether you choose a $50 room service breakfast and crackers for lunch and dinner or eat nothing until dinner?

Most large businesses have moved to the per diem approach or at least an approach where they look at overall reasonableness vs. productivity. In other words, the person who comes in way over time & again is a problem child, but maybe not if they are generating to dollar business.

The benefit of per diem is that it's a simple line on a form. Day x Rate = Reimbursement.