Zsh has a lot of features, and some can be actually useful. In my case, I find, for example, customizing the right part of the prompt useful; additionally, there are improvements that one gets out of the box, like better copy-paste.

However, when I've asked to colleagues of mine why they used it and how, I've found that nobody knew anything beyond the basics.

I've tried to go beyond the basics myself, but I've found the manuals very obscure, and I gave up. Nowadays I use it for my shell, while I use bash for scripts.

Considering that there's nothing radically better, or at least, that there's nothing radically better _and_ easily accessible, I think that it will always be either a niche, or a tool used in a very basic form. I also think it will realistically never take off in scripting.