It doesn't happen to me frequently anymore, but it's not terribly hard if you're tinkering and not super experienced (not a dig; this kind of slightly-beyond-your-comfort-zone tinkering is often a good way to become experienced). Install a couple packages from source, mix in a 3rd-party PPA, hand-edit a bunch of files under /etc, upgrade across a major distro version, and it's not that hard to get into a state where you probably could unwind things but it's so much easier to just reset the whole thing.
Edit: Phrased differently, doing the opposite of this advice: https://wiki.debian.org/DontBreakDebian is a great way to get into a situation where reinstalling is easier than fixing it.
For me it's usually related to modifying partitions, changing disks, OS upgrades going wrong, or some minor disk corruption.
It's not common, but if you manage enough systems then even rare things happen enough that you'll need tools like this in your tool belt.
I usually reach for a live-OS booted off a USB drive (Ventoy is good for having lots of OS options on a single USB drive) but I'd be interested in giving this a try.
I've been using my Ubuntu installation for eight years straight. The choices regarding the size of swap and the EFI system partition made sense back then, now they don't. I used to use Windows more often than Linux, now it's the other way round, so it makes sense to shrink Windows partitions and grow Linux partitions. I'm stuck with all sorts of legacy decisions that take time to redo correctly, and doing anything related to partitions online is hard.
Edit: Phrased differently, doing the opposite of this advice: https://wiki.debian.org/DontBreakDebian is a great way to get into a situation where reinstalling is easier than fixing it.