What makes Spin Launch a promising alternative to traditional rocket launches?

[hutchphd]

The acceleration in tangential direction - increasing the speed of the payload - can be done slowly, over something like an hour with an acceleration well below 1g, lowering the peak power.

So what? The centripetal acceleration will make you just as flat. The power will be less as you say.
If you want to talk about the rate of change of the acceleration (known as the "jerk" where I come from) then you you may have a point but I am not convinced it is very salient.

 

[Grinkle]

This interview / discussion / 'factory tour' was very interesting. I recommend it to anyone with interest in the spin launch physics, engineering and associated launch economics.