How Can I Help You? But Not Really.

Can someone please explain to me the POINT of an answering service? I have encountered several of them through various doctors and medical offices. Each time one answers my call, they say, "Such-and-such's office, how can I help you?" I tell them what I need. And then they say, in an almost exasperated tone, "Well, this is just an answering service. The office isn't open right now, so you'll need to call back when they are."

So WHY are they there? One might say, "Because that way, when customers call, they don't get voicemail or no answer." But if the result of speaking with an answering service is the exact same result I would get from no answer whatsoever, then I ask again--what is the point of an answering service??