So, why do we need to use Bitcoin???
to buy a new car 
LOL maybe this is absurd reason but this is my reason just wanna buy car
That's foolish to think of using bitcoin to buy a car. In future users might get a access to buy car using bitcoin, but as the above mate indicated using bitcoin to buy car is not possible. Better is to make a investment into bitcoin from the day job earning, which would help get a car with bitcoin in future as we can buy only digital goods and other few services for bitcoin.
Even not directly sending the bitcoin to the company but using a Bitcoin payable API endpoint,this transaction had been done as an evidence that could prove a car was actually ever bought with bitcoin
Some company had also been highly hyped a few years ago for reselling Tesla electric cars (if I'm not mistaken) for bitcoins. Obviously, they had been converting bitcoins to fiat prior to purchase since Elon Musk doesn't seem to be particularly interested in Bitcoin (whatever he might say to the contrary). So there is nothing new or sensational in this story as such, we have seen that before...
Though I don't know what's become of that company