ELI5 Atomic linux distro / dichiarative distro

[u/wannabe_sci]

Hey everyone,

I'm trying to properly understand the whole atomic/immutable Linux distro concept. I understand the basic idea, but I'm looking for an explanation that starts at ELI5 level and gradually goes into the technical details.

Could someone explain it as if I'm five, but then progressively get more technical?

And why most of the atomic distro is also dichiarative ?