Some designers factor grill into sound of loudspeaker some suggest removing for best sound. As far as protection most grills will not stop a lab or Child or from pushing in cone. But it does keep it out of site and with kids out of mind. With dogs as long as it doesn't have a smell they like you should be ok. My dogs love the smell of certain drivers they do not damage. But they approach to smell which means press moist noise against cone if you let them. And I don't. My cats where harder on my loudspeakers than any child or dog. Thus today no more cats.
