They do however have the potential (no pun intended) to act as a backup battery for the grid, to help overcome the variability of so-called "green" sources. It won't be long before we see tariffs offering cheaper energy to EV users who are willing to let their energy supplier choose when they can charge their car, via a smart meter.
At a conference a couple of years ago, an EV proponent was salivating at the thought of Heathrow's car parks full of EVs, 20 000 batteries connected to the grid for a period precisely known to the airlines and hence the airport operators... A bit like pumped storage without the water.
In terms of comparing energy sources, that's "a bit misleading", as are several other bits of "information" on that page. It's the sort of tactic used by the green lobby.
In this case, it conveniently ignores the conversion efficiency converting the chemical fuel to electricity at the power station. So lets say we were burning petrol at the power station, what's the efficiency there converting to lecky ? I suspect that from fuel to wheel is not much different.