The advantage of that, though, is that you can still benefit from the many "how do I do X in bash" posts on various fora, Stack Exchange, etc. With the more esoteric shells you have a much smaller community.
For scripts, you can still use bash or zsh or python or whatever you want.
I prefer to keep my utilities scripting and interactive shell the same. That way I don't have to keep two sets of gotchas in my head, and don't accidentally use the wrong syntax in one place or the other sometimes leading to confusing misbehaviours.
While I don't mix bash/zsh/sh/... I will consider python/node/other if I need specific things that they do well or I'm making something more than a simple tool or automation (for which bash is either underkill or just thoroughly unsuited). They are sufficiently different that I'm not going to cause myself the sort of mix-up I might with flipping between shell scripting syntaxes.