When booting into a live CD, mounting the various subpartitions is super annoying.
When your disk space hits full, things break uncontrollably because different programs don’t have a consistent measurement of how much space is left.
When shrinking partitions, you can lose data if you shrink it too much. I’m not talking about forced overrides of any configs, I’m talking about things like KDE Partition Manager.
All of these things can be excused one way or another, but at the end of the day I just want a stable filesystem that doesn’t lose my docs.