The UNIX shell is a primitive REPL, without the capabilities of the REPLs developed at Xerox PARC, TI and Genera, regarding structured data, debugging tools, function composition, inline graphics, ability to directly interact with OS APIs.
A car without infrastructure is just a fancy box.
A chariot without infrastructure is a rideable horse.
A rideable horse in the age of broken, disparate, infrastructure.
But, at the end of the day, it all depends on what you're trying to accomplish. I use repls, shells, notebooks, etc, on a regular basis. Unix tools solve some problems. Repls solve other problems. Notebooks another. What's important, to me, is to be able to be able to make the most out of them all, despite their flaws, because they're simply the tools that we have in our toolchain. It would be a shame to not learn our own tools, when they can offer us so, so much.
No need for language snobbery - the sanity of the "language" isn't what's being discussed here. We're talking about the capabilities of of unix tools within domains where they'd be used. If you want to use a repl within your domain, that's your choice, but understand that in doing so, you're working with a relatively limited domain compared those within the reach of unix binaries.
