I think you got it exactly right, apart from the fact that an "average" desktop Linux user is like 30% [1] company/university computer. For those users it's probably very useful.
Also it's useful for your average Joe. Joe don't want to mess with his system, so immutability is his additional layer of security. It's not thing for tinkerers, it's meant to be same base on every system, and everything else is container.
I think you got it exactly right, apart from the fact that an "average" desktop Linux user is like 30% [1] company/university computer. For those users it's probably very useful.
[1] a completely uneducated guess.
Also it's useful for your average Joe. Joe don't want to mess with his system, so immutability is his additional layer of security. It's not thing for tinkerers, it's meant to be same base on every system, and everything else is container.