While I never used a Mac before OS X, they probably were quite usable, and your question was both rethorical and snarky. There is more than one way to use a "computer". Incidentally, I only switched to the Mac after they added a shell to it with the switch to OS X. And one of the reasons I disliked Windows was the crummy shell and lack of a terminal. Also, it is 2019 and it is no problem to get a full Linux installation on a smartphone, while Apple sets up artificial limitations to prevent that.
There are certainly other ways to make the iPad a computing device - like the Macs before OS X, but Apple steps into the way of that in many places too. An app like Termux would not only make a lot of potential users happy, it would be something which could provide this in a way which could be nicely sandboxed in the iPadOS/iOS.
Naturally it was snarky, because having a CLI to be an usable computer is not something that one can generalize and largely proven in the market that consumers don't give a damn about it.
Which phone is sold with a full Linux distribution, with any kind of market relevance?
Android certainly not, as regular Linux APIs aren't part of the NDK stable API list, which Termux actually needs to work within the constraints of ISO C, ISO C++ and NDK APIs.
I still don't understand why you felt it necessary to make a snarky comment. Yes, there are tons of users who never use command lines on their computers. I guess no small amount of the Mac users don't know what "Terminal" is for. But do I really on hacker news have to argue what the value of a command line for an advanced user is, especially the hacker news audience?
Maybe because REPLs are more powerful that an plain old command line, and specially the HN news audience should be aware of it, given that it is built on top of a Lisp variant?
Being a developer is not a synonym for being stuck with a PDP-11 concept of how a computer is supposed to be used.
The commenter you answered on was talking about a terminal app for the iPad in general, how do you get to repls from that? And if you want to talk about repls, why don't you do that in your original comment? You should look at the Hacker News guidelines, which in the very first item cover your post specifically.
And you don't need to teach me about repls, I am a full time Lisp programmer :).
Because something like Swift Playgrounds, but in the context of iPad automation is from my point of view the ultimate goal, lets call it the Dynabook Smalltalk transcript, not just replicating a green phosphor VT-100.
I always think this is such an odd sentiment. That 1% builds 100% of the software for the other 99%. Doesn't that make them disproportionately more important?
Liking using something is a bit different than having to use something. Are you saying you don't think the majority of developers need to use the command line for things like git, npm/general dependency management, running local web servers, compiling apps, continuous integration, etc...?
There are certainly other ways to make the iPad a computing device - like the Macs before OS X, but Apple steps into the way of that in many places too. An app like Termux would not only make a lot of potential users happy, it would be something which could provide this in a way which could be nicely sandboxed in the iPadOS/iOS.