Why do couriers exist?

I ordered a book recently, and for some reason the company decided to use a courier instead of mailing it (presumably because they wanted it to be as inconvenient as possible), so obviously I missed the first attempt to deliver it because if I'm at home during the day I'm not awake before 10:00.

But that's OK, there was a number to call to reschedule. So I organised to have it redelivered today.

"Will you be home between nine and ten?" asked the man.
I said "yes", because I can be up that early if I need to be, it's not a big deal. So I got up at nine, and I waited.

At ten, I started to get a bit annoyed, but I decided to give them a bit longer.

At ten-thirty I phoned the number again and asked what was happening. Now, the interesting thing here is that this phone number was the mobile phone number of the actual guy who'd made the first delivery attempt, so all I got from him was "I'm not working today, but I told them to deliver it."

Fine, I'll have a look at the website. There is a package tracking system there, but all it tells me is that "the parcel is onboard the Courier vehicle" and has been since 7:30 this morning. No indication of when it might be arriving.

Finally at quarter-past eleven the package arrives and I sign for it and the courier goes away. And then I notice on the packaging, written quite clearly "Deliver 9 - 10". What's the point in even having instructions like that if they just ignore them and show up whenever they get around to it anyway?

And more importantly, why not just use Australia Post? They may not actually make genuine attempts to deliver things (because walking all the way up the driveway is such a hassle) but at least they don't make you reschedule, they just tell you to come pick it up from the nearest post office, which you can do at your convenience any time within the next couple of weeks.

What is the actual point of couriers? They just seem to do the same thing as Australia Post but less well. Is there some advantage here I'm not seeing?

I don't get this ad

If publishing your secret angers doctors, that usually means it's dangerous or unhealthy. If it also makes your face bleed when you do it, that's definitely a sign that you should stop. Also, that woman doesn't look 27.