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