It's not a flying car, it's a shitty car that can with some effort be turned into a rather shitty airplane. At that point it's functionally an airplane, doing everything an (shitty) airplane can do and none of the things a car can do. When it's turned into a car again it can do none of the airplane things and only do everything a (shitty) car can do.

Calling it a flying car is just playing on peoples fictional vision of what a flying car is and then leaves them disappointed when they see this thing.

Not to say it isn't a marvelous piece of engineering and deserving of admiration for this, but more in the way we admire a piece of art.