"Ubuntu Core" is a similar product [1]

As I understand it, the main customers for this sort of thing are companies making Tivo-style products - where they want to use Linux in their product, but they want to lock it down so it can't be modified by the device owner.

This can be pretty profitable; once your customers have rolled out a fleet of hardware locked down to only run kernels you've signed.

[1] https://ubuntu.com/core