Shaving valuable minutes? Really? Let's put that to the test.
Obviously, whether valuable minutes get shaved depends on where you're travelling from and to. I'm going to assume you want to travel from the ExCel Exhibition Centre to the Dome, because these are by far the largest visitor attractions on each side of the river. I'm also going to assume you're on foot, not on a bike. How long would it take to travel from the western end of ExCel to the entrance to the O2? I've been out with a stopwatch wandering the area and riding trains, and this map summarises my findings.
Grey: Jubilee Blue: DLR Red: cablecar Green: walking (all times in minutes)
Currently, if you want to get from ExCel to the Dome, you do this: a)walk from ExCel to Custom House DLR (across the walkway and down to the platform) = 2½ mins b)wait for westbound DLR train = X minutes (total so far: 2½+X) c)DLR from Custom House to Canning Town (3 mins) and down to the Jubilee line platform (½ min) (total so far: 6+X) d)wait for southbound Jubilee train = Y minutes (total so far: 6+X+Y) e)Jubilee line from Custom House to North Greenwich (2 mins) and up to the surface (2 mins) (total so far: 10+X+Y) f)walk from North Greenwich to the Dome (across Peninsula Square) = 2 mins (total: 12+X+Y minutes)
Time: Although the journey can be done in as little as 12 minutes, I did it yesterday in 15. I was lucky because I had quick changes (2 minutes at Custom House and 1 minute at Canning Town), but I'd have taken longer if connections had been poor. Most of the week X is a wait of anything up to 5 minutes, and Y anything up to 4, which would suggest a typical maximum travel time of 12+5+4=21 minutes. Cost: I have a travelcard, so this cost me nothing (on Pay As you Go it would have cost £1.30) View: rubbish
In future, if you want to get from ExCel to the Dome, you could do this: a)walk from ExCel to Royal Docks cablecar station (down a tedious boulevard between hotels) = 5½ mins b)enter the cablecar station (no idea how this will work, so a notional time here) = ½ min (total so far: 6) c)cablecar journey across the Thames ("serene and joyful") = 5 mins (total so far: 11) d)walk from Greenwich Peninsula cablecar station to the entrance to the Dome = 4 mins (total: 15)
Time: 15 minutes, which is exactly what I did it in yesterday. No valuable minutes shaved off. Cost: yet to be decided (but likely to be at least £2.50) View: "truly spectacular"
Comparison: The cablecar isn't a huge timesaver. It's 12-21 minutes from ExCel to the Dome by DLR/tube, and 15 minutes by cablecar. You might shave valuable minutes on the Emirates Dangleway or you might not. The view will be better, but it'll cost you more.
But: These are the timings if you're at the western end of the ExCel exhibition centre. If you're at the eastern end, then it's at least a ten minute walk to the cablecar, so you should definitely take the DLR from Prince Regent, then the Jubilee.
And yet: Other journeys are available. For example, I can guarantee that the cablecar will be the quickest option if you want to travel from the Spar shop by the hotel south of Royal Victoria station to the car park near the shut-down David Beckham Football Academy.
Conclusion: The cablecar is for tourists, because it has a nice view, not because it joins anywhere important fast.