At about 10,000Gs of acceleration (as per their claims¹ ~2200m/s in a 100m vacuum chamber, e.g. a=v²/r ≈ 97,000m/s² or roughly 10,000Gs) any human passenger would be liquified and form a nice smooth film on the inner surfaces of the vehicle.

¹https://www.spinlaunch.com/orbital#p2

How many SpinLaunch to launch the same amount of Cargo compared to a single Starship.

With a 100m arm, the will launch only like a few 100kg, a single Starship can launch 150tons.

Why in the world would anybody use spin launch?