I tried to use a $200 e-cert, and by the time I got it processed I would have been better off spending my time earning that $200 at work.

I'm a bit new to this, but why is an e-cert not simply a discount off a published fare? I understand why there are restrictions like blackout dates, expiration dates, and limitation to use it on a single booking (can't split across multiple Pax).

But why can't I use it multi-city (especially when it's IAD departure, DCA return), or on an itinerary with multiple pax (just apply the discount to one of the fares)?

Why all these other oddball booking restrictions that don't seem to have any purpose?