Also having everything system specific live under a single path means easy backups, easy immutable trees that can be A/B swapped for seamless and online updates with easy rollbacks.
No more wondering where the various tools live since everything lives in /usr/bin and more.
The original point of a non-merged /bin was that /usr/bin was a spillover from when they ran out of space on the primary drive back in the 70s, so there was a slapdash split where the stuff necessary for bringup was kept in /bin and the rest would be kicked down to /usr/bin, in a very inconsistent manner depending on the system’s evolution.
In fact that’s also why users were moved from /usr (the original location, hence the name) to /home: /usr ran out of space, so they added a third disk and moved the user directories over there.
> Keep in mind that the approach of booting from initrd is quite non-idiomatic
How can you claim that it’s non-idiomatic when it’s the standard approach?