Fluff a late game war, steal Computers, build Internet, build SE, nab a Space Race victory from under their noses?
I'll let y'all know if it ever actually happens to me...
Now that you mention it . . .
Let me, very carefully and somewhat reculantly, enter the discussion about the Space Elevator. I just played a game where it did indeed save some turns, not many probably, but certainly a few.
The background:
As Gandhi I roll a 2 gem (I never get these starts, but boy are they fun) start on an island with one AI present, Augustus Caesar. I decide to maximize the gems and went Oracle → Feudalism. My wandering warrior meanwhile pops three huts for Experience (I know, weird game) and ends up WoodIII after the uncontested barb bashing he did. I then wander up to Rome just in time so see 2 Archers and a Settler venture out of the city. I DoW the Roman scum and park WIII in a forest, which of course strikes fear into the heart of Augustus who recalls his expansion party. A few Longbows and Catapults later, Rome is under my control and Caesar's empire is no more. This leaves me with a big and beautiful island and zero trading partners. I had gone Feudalism with the idea of getting Augustus to capitulate but you know how that goes, Rome was pretty and I wanted it all to myself.
The Finish:
Elsewhere in the world, Brennus is taking vassals like an alcoholic orders drinks, quickly and without much introspection. With Mehmed, Willem, and Washington under his command and Ragnar as his War Monger Shared Religion buddy he goes WHEOOHRN and we know what his destination and my destiny must surely be.
I was obviously behind in tech, isolated as I was, making it logical to build the internet anticipating a Space Race tech frenzy. I want Laboratories so that puts me with Computers already researched knowing that Brennus, with his large and experienced army and his three vassals will be visiting soon. Knowing that I want to 1) defend my cities and 2) win the Space Race quickly (Brennus was going Culture) teching Robotics was the most attractive option, I'm killing two birds with one stone.
Why waste hammers on the SE when I needed to build an army immediately? Because my collection of GP that I intended to use for GA's during the Space Race included two GE's. This means I had one for a Golden Age and one for the Space Elevator. I had a decent Ironworks city and built the elevator in about 5 turns thanks to the GE. By the way, Mining Inc and Creative Constructions were founded long ago ruling out that possible use for the GE.
After eliminating the sizable invading stacks I returned to building SS parts aided by the 50% bonus. While not a typical game it seems to me that the SE was, in this case, not useless and did speed up the victory as I finished my last two parts within one turn of each other with each city benefiting from the SE bonus.
I should mention that Brennus made the mistake of building the Manhattan Project thus allowing me to apply Physics to the problem of his third city that was quickly approaching Legandary status. He really should have built the SDI immediately following Manhattan, let that be his lesson.
I must say it was one of the funnest games, particularly the start and the finish, I have played in some time. A real thriller with a guest role for the SE.