Back in the Day, it was BSD Unix, which used tcsh as the interactive shell and Bourne shell as the scripting shell, as tcsh had tab completion but has a scripting syntax which is harmful to sysadmins and other living things, and Bourne shell had a sane scripting language but no interactive functionality beyond cooked mode.
We developed Korn shell, Bourne-Again shell (bash), and, eventually, zsh to move beyond that idiotic experience. These days, our non-interactive scripting languages are Python, Perl, Ruby, and Ruby with a different mix of libraries, all of which have better FFI other support libraries than any shell does.
My point is, unless bish has Python-class libraries, I don't see the point of taking on the annoyance of having a scripting shell different from my interactive shell.
Back in the Day, it was BSD Unix, which used tcsh as the interactive shell and Bourne shell as the scripting shell, as tcsh had tab completion but has a scripting syntax which is harmful to sysadmins and other living things, and Bourne shell had a sane scripting language but no interactive functionality beyond cooked mode.
We developed Korn shell, Bourne-Again shell (bash), and, eventually, zsh to move beyond that idiotic experience. These days, our non-interactive scripting languages are Python, Perl, Ruby, and Ruby with a different mix of libraries, all of which have better FFI other support libraries than any shell does.
My point is, unless bish has Python-class libraries, I don't see the point of taking on the annoyance of having a scripting shell different from my interactive shell.