Is Emergency Build useless?

[Stone Mill]

I using EB sparingly; but PvK gave good examples:

* When there is an emergency in one area of the map (i.e., enemy invasion) and you want as much built as fast as possible, to maximize the response. (Gee, am I the first one to mention using emergency build for emergencies?)

* When something is down to 0.2 years to complete, and emergency mode will reduce it to 0.1. By cancelling emergency mode the next turn, you get 25% more production than you would have otherwise, which is also a good time to buy something cheap that you wouldn't have wanted to spend a whole turn on.

I don't want to give away any BIG secrets of my strat but it has very much to do with maximizing construction rates by building designs to meet current production output. The colony ship example:
If a colony ship costs 4500 to produce and your standard production rate is 3000, it is quite efficient to use EB... (I believe Pax touched on this as well. But care is to be used and only a small percentage of your worlds should use it at any given time.

For the emergency scenario, if you are in a pretty large galaxy and have control of many systems, you can't defend them all, so you would use EB on frontier systems to produce reinforcements a bit quicker ( and pray the threat is squashed within 10 turns!)