It's more akin to locking your front door. Keep it locked if you want the extra protection but feel free to crank the door open if you want the breeze to come in, but knowing that more than the breeze might do so.
Last I used a Mac I remember trying to create a new directory in / and writing to /bin (or something like that). I was appalled that Mac doesn't let you do anything other than read-only operations for select paths a few levels under root, and as I remember, there way no way to disable this asinine behavior.
Freedom does not just imply the ability to do the things you want, but also the ability to avoid the things you don’t.
What's the point of this exercise? Is this some kind of power play against the... operating system?!
Did this prevent you from achieving anything?
In any case, I'm fairly confident if you disable SIP and do a couple extra steps, you can get write access to those.
Being interested in this project and simultaneously disappointed it requires SIP to be disabled are not conflicting views, even if a little unfortunate for me personally.
Given the numbers of UNIX devs that rather use macOS than either pure BSD or GNU/Linux, that prison is quite comfy.
It is just computer.