Earlier quoted context omitted.
I agree... and any well written script will have a shebang that specifies the shell that shluld run it, anyway. For me, personally, I love having homogeneus systems put in place. In this case it means not having to switch my mind between in and for modes. Helps me avoid mistakes, having to keep less context up here. But it's always interesting to read about other people's way of working.
If you want to make the systems homogeneous, then you need homogeneous teams, too. Maybe some team members prefer fish, others prefer zsh, still others prefer bash. Your suggestion means that everyone has to use the same shell for their command line. I find that it is better to allow each team member to have their own working environment: different (command line) shell, different editors/IDEs, different keyboard shor…
But of course, I believe others should be free to make their own choices! As long as their choices don't end up affecting the quality of the code that ends up shared with the rest of the team...
Which brings an interesting point: I don't have a problem at all with you using whatever shell you want. But I do have a problem if because you don't use Bash in your day to day, you are less used to its ins and outs, you don't put in the extra work that is being as proficient with Bash than you are with your personal shell, and your scripts end up with bugs in how Bash arrays are treated (just a quickly made up example)