Energy density is "good enough". Cities like New York banned helipads on the top of high-rises after the Panam crash in the 70's because of the risk of jet fuel flowing down a high-rise and igniting.

Electric powered vehicles like this would solve that issue and allow quick travel around high density cities, they could land on top of buildings to pick up passengers. Current battery technology should be enough to support these short range trips around a city.

A good example would be a corporate executive traveling from their NYC headquarters to the local airport to board their business jet. It's not a long distance trip but helicopters are not suitable.

One thing to keep in mind, though, is that internal combustion engines are quite inefficient, piston engines typically convert less than 20% of the chemical energy into work. Electrical engines are much more efficient, so that gives you a factor of about 5 to 10.

In other words, getting batteries with, say, 4 times the current specific energy would already make a lot of electric flight applications practicable.

At the current rate of improvement (5% to 8% per year), we should be there in about 20 to 30 years :-)

This is an electric VTOL craft which runs off an energy source that is renewable, unlike jet fuel. If it can be done that is what should be important here.