The NEWS entry is part of the Debian packaging. Tools like apt-listchanges will display relevant NEWS entries when updating a package.
Bookports is the best way to run newer versions of packages on a stable Debian system, since those package(s) will be part of the next stable release ensuring a clean upgrade path. Due to apt repo priorities, packages from backports will never be selected, unless explicitly listed during an install/upgrade command, or a version from backports is already installed. Usually this works just fine, but when a binary package reorganization occurs (like with incus 6.0.3-3), or a new dependency is added that’s only available from backports (like a newer version of QEMU required by Incus), apt can’t automatically resolve the situation. It will do the best it can, such as upgrading incus-client but not incus.
The dangerous bit of apt dist-upgrade I listed above is the -y option; that causes apt to automatically apply its “best” solution, which can involve automated removal of packages.
I routinely use backported packages on my various Debian systems, but remember the disclaimer on the front page: “Backports cannot be tested as extensively as Debian stable, and backports are provided on an as-is basis, with risk of incompatibilities with other components in Debian stable. Use with care!”