Not sold on declarative systems in all domains. It often creates unnecessary complexity for little advantage.

Immutable root has huge benefits in large deployments for consumers, enterprise or servers. Really great for Chromebooks and consoles. Probably would benefit the majority of Windows installations, certainly in enterprise. I do not like the idea of critical systems being updated with random shit becoming standard practice as in WIndows/Clownstrike land. Those guys have normalised insanity to the point they think we are the crazy ones.

However I like to mutate my desktop and development systems. I use linux because I like the freedom to tinker and that includes the freedom to mess stuff up. In practice having root writable only by a privileged user, a signed software distribution and knowing what I am doing mostly keeps me out of trouble. On the very rare occasions I find myself without a bootable system (it has happened to me more than once in 30 years) I know how to recover and it doesn’t stress me.