Depends.

An overflowing queue that drops jobs from the front while backend chugs along as fast as it can, is for many cases a better outcome than the backend overloading and everything grinding to a halt.

Compare it to a physical service desk. The one that has a queue, serves one person at a time, and people arriving will try again another day if the queue is too long. The one without queue has people fistfighting over who gets to go first, and no one ends up getting service.