I'd have to agree, a 48 hour coupon is almost worthless.
I don't know, plenty of people got use out of it. I've learned to always be careful on the last day of something. Everyone always assumes it runs through like 11:59 PM or whatever, and everyone who does sales/coupons does it differently.
One of life's many lessons - and there will be other coupons for frequent Demigod players. You missing the deadline because you decided to postpone it doesn't make it generally worthless, I saved quite a bit of money
And HorseRadish, stop being an ass. They're not responsible for checking if you're on vacation or not when they send them out. Keep playing and you'll get another coupon too.
Edit: The only people who actually have a right to complain about coupons are those who can only use Paypal.