Real world fedora atomic distro security?

In my (somewhat limited) experience, if you frequently update without restarting, the atomic distros are actually nicer to use. Because you don’t have to worry about time between update and restart. You do still need to restart before the update will apply. But, because atomic updates are ‘applied in full, or not at all’ there is no risk with not restarting right away, because the update command doesn’t actually update anything, it just downloads and prepares the update which will be applied whenever you restart next.

If you stick with a traditional version of Fedora, a potentially useful command is dnf needs-restarting (as well as dnf needs-restarting --system) these commands can give you more insight into when a restart is required. But realistically, its easier and better just to get in the habit of restarting after updates. Cleanest way to update, quickest way to get the latest packages, and just overall good for digital hygeine in my opinion

dnf needs-restarting man page