Hi, I am new to the forum and i will give my go to why they didn't supply a jack with the car.
I believe that the car is so stiff that a normal automotive jack might not be strong enough to lift it. Normally when you lift a car, the oposite diagonal suspension is compressing. If the springs on the car are so stiff that doesn't allow for that much compression, you will need to be actually lifting all the vehicle. Now, quite a few jacks have been mentioned to give away while the car is lifted because of material weaknesses.
There, i said it.
Didn't say that it will make sence