Of course the flying Tesla Roadster is a gimmick but that sort of misses the point, the tech flex behind it isn't.
Tesla's bulk business is about advanced technology from EV to self drive, but decided to create the most ridiculous manual drive supercar. Supercars are a gimmick,almost by definition, based on how wild can you make them.
The gimmick that can make the car literally fly, briefly, can make it corner like no other supercar and accelerate, literally like a dragster on a test track. It's got nothing to do with flying continuously, but having a car that will outperform every Lambo, Ferrari or McLaren with technology that they cannot replicate because it requires experience from space launches and computation that they don't have now nor will in future.
So Porsche, Bugatti, Aston Martin just became legacy prestige brands, like Rolex, Richard Mille or Patek Philippe. These cars celebrate the bygone age and the baroque, physical complexity of the internal combustion engine just as mechanical watches do for non digital, complex time-keeping mechanisms. But hey won't be faster anymore than a mechanical watch keeps better time than a Casio. They are now, de facto, mobile jewelry and no longer supercars with superlative performance. And this affects their ability to market the bulk business of mainstream European internal combustion engine cars. It's the end of an era of industrial era manufacturing.
I hate to be the one to burst the Tesla bubble today, but the spectacular “flight” we witnessed at the Roadster reveal needs a little context. The car is carrying around 250kg of compressed air, plus the weight of the tanks, valves and thrusters needed to contain and release it.
Based on the published figures, that gives it roughly 1.5–2 seconds of maximum thrust before the system needs to be refilled.
In short, it's a gimmick.