Pretty much what acsimpson said.
Lower pollution (yes, the electricity needs to be produced, but that's also gradually moving to greener solutions, and in terms of local city pollution it would be much better).
Congestion, it clearly does nothing to solve.
So what we need is better public transport + cycling infrastructure + walking infrastructure, and where there is a need for motorised vehicles (recognising we're never going to get rid of them entirely from our cities*) a cleaner electric version, which doesn't belch out fumes (or noise) is a better solution.
Also Tesla is advancing the technology very well, and above all else is really putting this into the public consciousness. This is headline news on the BBC website, which is a big deal. And as far as I'm aware they're actually quite generous with their findings on the tech, so it will move into other vehicles, and how much nicer would Edinburgh be is buses were all electric rather than diesel?
So to go all Monty Python, what did that Tesla ever do for us?
*I'd argue that believing we will eradicate personal motorised transport from cities in their entirety is pie in the sky. Wanting to is a lovely utopian daydream I also indulge in from time to time.