Not all distros use point releases.
You have things like arch and gentoo which are rolling distros.
Debian is a semi-rolling distro if you set it to track the “testing“ repository. Also if you set it to track “stable” instead of the code-name for the current stable release, when a new version of stable is released, your entire system will be updated from the new stable branch.
And many point release distros offer an upgrade path from one point release to another. For example with Ubuntu it’s possible to update from one LTS version to another. Upgrades from non-LTS versions are not always possible.
So in many cases, whether a distro is rolling, or not -the point releases of their installation media are for first time installations.
Once you have a particular distro installed, it’s often possible to update to a newer release.
Some distros might require a complete installation from scratch using the new point release, but I think distros like that are in a minority nowadays.
With the point release distros, the focus is on having a stable and secure desktop experience for users using a sane set of software and a sane default configuration. So it’s not always appropriate to have the very newest versions of packages installed.
They’ll use older, better tested packages.
With rolling distros - the focus is on having the latest and greatest, most up to date packages installed. But that can be a double edged sword, because you potentially also have the latest and greatest bugs, vulnerabilities and performance regressions. So it can have an effect on the stability and security of your system sometimes.
It might not happen often, but it does happen from time to time. And sometimes it takes a while before the most serious issues are fixed.