Somewhere in that video someone mentioned 3s to 100km/h (a hair under 60 mph). That's pretty brisk acceleration, though I seriously doubt it will be true, even if they have some ridiculous gearing that would limit top end speed. The Vectrix has a slightly stronger motor in terms of kWh and 110km/h electronically limited top speed, yet managed a time of only something like 6 seconds if not longer... Even the Zero SR can't do 3s to 60mph with its several times more powerful motor, so I highly doubt these things can even come close.
A bike like this will be more powerful than 50cc gas bikes for sure. Based on my experience with the Vectrix, which was similar to a 300cc or more up to its top speed, these would easily keep-up with or beat a 125cc off the line and probably be competitive up to top speed. So I would not discount them on performance. I think they would be great in the city, just not as quick as a Zero.
Will Zero compete with these? Sure, it might get some buyers like those who want something a bit more than a 50cc scooter but don't want a big motorcycle and would otherwise have bought a Zero S reluctantly. Although I highly doubt there would be many like that, especially in the target markets in countries like India, where these things will need to be priced very low to have any chance of sales, way lower than a Zero.