/usr/bin is under the control of your package manager _ unless you're building and installing packages for all your adhoc scripts, aren't you worried about name collisions?
I keep ~/bin for easy version control/backups of my own scripts. I don't want to make a directory/repo for each script, and for getting them on PATH I can either add ~/bin to PATH or remember to run ln -s ~/bin/* /usr/bin/ after adding a script. Adding to PATH has saved me a few seconds of minor frustration at no cost.
I can't write to /usr without root, and I can write to home. I also personally like a clear delineation between things that are managed by the package manager and by myself.
It started out as a separate drive for home directories and files that didn't fit on the first drive. cf. /usr/dmr (Dennis Ritchie), and /usr/ken (Ken Thompson).
‘Users’ because that's where users' home directories were, like /home in Linux FHS or /Users in Mac OS. Then acquired overflow versions of bin et al. when the root disk filled up.
No, this is my laptop - /usr/bin is the place for that. No, this is a simple server - /usr/bin is the place for that.
Perhaps I'm missing something after 23 odd years of using Unix systems including this Arch laptop.