It means that if someone decides to get away from this legacy structure and move OS into something like /system/debian-11.1.2/ all those programs would break.
Examples: [1], [2]. I assume that developers have hardcoded those paths because /sbin is often not included into PATH.
[1] https://github.com/blueman-project/blueman/blob/fcef83a01c80...
[2] https://github.com/blueman-project/blueman/blob/fcef83a01c80...