Earlier quoted context omitted.
Related, I work with industrial control systems. We’d call this “smoke and mirrors”. Sometimes the client would insist on seeing a small portion of a large project working well before it was ready. They’d misunderstand that 90% of the bulk of the work is not visible to the user but they’d want to see a finished state. We’d set up a dummy HMI and have someone pressing buttons on it for the demo, and someone in the nex…
To me it sounds like a useful thing, for communicating your vision and getting early feedback on whether you are building the right thing. Like uh, a live action blueprint. Let's say the client is like "Email???? That's no good. It needs to be a text message". Now you have saved yourself the trouble of implementing email.
It’s called prototyping, in this case it would be a hi-fi prototype, and it lets you communicate ideas, test the implementation and try out alternatives before committing to your final product.
Lo-fi prototyping usually precedes it and is done on pen and paper, Figma, or similar very basic approaches.
Google (unsurprisingly) uses it and has instructional videos about it: https://youtu.be/lusOgox4xMI