When this tool becomes as available out of the box as POSIX sh (i.e. practically everywhere, including embedded systems and containers), then this reversed argument will make some sense. I'm willing to bet anything that POSIX sh will still be with us 50+ years from now, and 'just' will be long forgotten by then. You really should have a stronger argument for introducing another dependency into your build process (and onto your developers) than "it has a slightly simpler syntax compared to the industry standard".
It's great that POSIX sh is available everywhere except where it isn't (Windows).
In all SW teams I've been in except one, sh was available, and people preferred writing things in something else (usually Python/Perl). I have had an order of magnitude more success convincing teammates to use just than convincing them to use sh.
It may be ubiquitous, but it's useless if you can't convince non-shell gurus to use it.
It's not "slightly simpler", it's massively simpler. Shell scripts are pretty much the worst syntax in existence (barring esolangs that go out of their way to be weird).
