Because it isn't possible. There is no way to fully automate the decision of what disk your system is supposed to be booting from and whether grub should be installed there. That is why the information is stored in grub-pc/install_devices.
Because it isn't possible. There is no way to fully automate the decision of what disk your system is supposed to be booting from and whether grub should be installed there. That is why the information is stored in grub-pc/ install_ devices.