It's just simple courtesy for one reason, and terms and conditions for another.
As part of the T&C's, Samsung are to inform anyone of delays on the pre-order in advance:
My own order for example, I had the text last Tuesday to say there was a delay until 'Sunday the 9th of September' (which isn't even a Sunday), and then a retraction text last Thursday apologising, and reaffirming that the delivery will arrive as expected (Friday, the next day).
It did not arrive the next day, and I had taken a day at home to be there for it.
I have called support pretty much daily and had differing stories as to what's happening, been promised (literally) that I would receive communication within 12-24 hours, which was 2 days ago, etc etc.
What adds insult to injury here is that order status still shows it will arrive a week in the past, and the website still proudly showing you can order and receive it.
"so a little short fall or a slight delay isn't the end of the world" - You're correct, the world isn't going to implode or set the atmosphere on fire as a result of a smartwatch delay, however some of us need to plan around a delivery, not be told it will be dispatched in '24-48 hours', every 24 hours, I can't do much with that.
It's the lack of any communication that's the problem (at least in my eyes), and they have broken their own T&C's by doing so.
Pre-ordering, as jPohn's reply already says, is used to gauge interest and have a known quantity of orders ahead of time, so you can more accurately plan your release and distribution.
https://en.wikipedia.org/wiki/Pre-order
"Surely the fact you're 'pre' ordering means they don't know the exact date the items will be available" - If I called and told you 2 weeks in advance that I would like a dozen cakes, and paid you in advance, you would know ahead of time what you need to provide, as opposed to me showing up on the day without warning where you may not have enough ingredients to fulfil the request, and have to delay and/or cancel the order. Surely this makes sense?
