"bash, obviously for scripting;"
It's possible to use bash for both interactive use and scripting. For example, this author claims to use bash as his scripting shell.
But Debian and the popular Debian-derived distributions do not use bash for scripts beginning with "#!/bin/sh", i.e., "shell scripts".
The interactive shell may be bash, but the scripting shell, /bin/sh, is not bash.
https://www.man7.org/linux/man-pages/man1/dash.1.html
https://wiki.ubuntu.com/DashAsBinSh
https://wiki.archlinux.org/title/Dash
https://www.oreilly.com/library/view/shell-scripting-expert/... ^1
https://www.baeldung.com/linux/dash-vs-bash-performance
https://en.wikipedia.org/wiki/Almquist_shell
https://lwn.net/Articles/343924/
https://scriptingosx.com/2020/06/about-bash-zsh-sh-and-dash-... ^2
I use an Almquist shell, not bash, for both interactive use and scripting. I often write scripts interactively. I use the same scripts on Linux and BSD. I restored tabcomplete and the fc builtin to dash so it feels more like the shell from which it was derived: NetBSD sh.
1. "This makes it smaller, lighter and faster than bash."
2. "... this is strong indicator that Apple eventually wants to use dash as the interpreter for sh scripts."
"/bin/sh does not point to bash" is not the same as "does not use bash for scripting"
On my system there are 42 scripts in /bin -> /usr/bin (merged) that start with some variant of `#! /bin/bash` and at least two that do `bash -c`, but that's excluding who-knows-how-many scripts that look slightly different or are in other directories.
And keep in mind that on Debian, almost all first-party software is implemented in Perl, with a small minority in Python.