In my experience, gaming distros primary benefit is being preconfigured with apps and patches you’d install on a normal distro.
For normal distros, this difference isn’t big enough to impact your distro choice in most cases. The reason these get recommended is due to their post-install setup being easier than the distro its based on, hence being friendlier to new Linux users.
However, for immutable distros this is a big factor as it reduces the need for layering. Layering makes updating much slower, so less is always better.
Not necessarily. When Ubuntu 22.04 had an issue where systemd-oomd was killing apps that touched the swap, something like this notification would have cleared up a lot of confusion from end users, myself included.