Can you not separate these worlds? I.e. use an interactive shell like this or fish for your day to day, and still write bash scripts where needed on your server?
I'm probably missing something though.
You can. Though you miss all kinds of ready to paste code, tutorials, tips, plugins, functions, autocompletions, etc. you can find for established shells...
Agreed. This is one of my biggest regrets for not following POSIX syntax more closely. So much so that I did at one point start writing in support for inlining Bash (and others) code into murex as a way of allowing users to make use of the rich content already out there. But I couldn't decide on a clean way of implementing it that wasn't any better than `bash -c 'some code'` so ended up removing the feature.
As it is, I'm still half tempted to incorporate a bit more POSIX support to make code sharing easier. But there's a real risk that I could compromise the design goals of my own language in doing so.
I think this is projects like Oil Shell (https://www.oilshell.org/) have the upper hand. It's gone for Bash compatibility plus new features. I have a lot of respect for what they do as it's a much harder undertaking than what I've done.