It's a matter of perspective and goals. If I just wanted a browser and access to VMs or cloud environments I'd use a tablet and a bluetooth keyboard. You can't learn things like changes in kernel configuration options, boot processes, graphical environments, etc. simply by using someone else's default configuration, only by reading and configuring yourself. Are these things critical? Not for most people, but they certainly inform my work in many ways and I would not consider time invested since the 1990s to have been wasted. Many people enjoy learning and are able to leverage knowledge for creativity, I am merely one of them.

Yeah. Often a gentoo root system becomes inoperable because it's out of date or has some weird package configuration. Using a snapshot-capable root allows you to easily swap it out to something known good or freshly installed and keep running.