If we make a distinction between CLI apps and TUI apps, my interpretation is that the article was specifically talking about the latter.
By a CLI app (with the emphasis on command line) I mean something like grep, sort, cp, git, ls, tar, etc. The normal way of interacting with these is by writing commands on the shell, which means that if you know how to use it normally, you can also use it in a script. Which means that you can combine these into pipelines.
By a TUI app I mean (and I think the article means) something like Vim, Emacs, Tmux, Lynx, Tig, Midnight Commander, Claude Code, etc. - an interactive app that takes over your terminal while you're using it. You're not going to compose those into a pipeline. Or to be more precise, you're not going to use them in pipeline by using them the way you normally use them. If you can use them, it's probably because the app decided to provide a command-line interface in addition to the TUI.