My understanding is that the skateboard would have to be too thick to fit within the shorter wheelbase, substantially raising the occupants, etc. I think this also plays into the chassis design since they say they can build the "chest" design as part of the chassis. I think the skateboard requires more of a traditional body on frame. This is sort of a guess though, but slightly based off of the explanation of how they designed the chassis of the C7 Corvette to be light and more rigid.

Edit: thanks for the additional link

You want a low center of gravity but also weight in the center of the 4 wheels of car, that's why most sports cars nowadays are 'mid-engine'. Weight in the center helps in turns since the car wants to rotate around itself.

Smaller moment of inertia at the same weight.

> The article mentions a lower height

There’s also an emotional component in the difference in perception of driving at 250 Km/h on a BMW 750 or in a Lotus where your seat is hugging the road under you.