This concierge approach is nothing new; it existed even before LLMs are a thing.

One of my courses in undergrad computer science is Human-Computer Interaction, in which we learn about user experience (UX) concepts.

One of the things we learnt is to validate our ideas quickly and cheaply before putting a lot of time, effort and money into building the thing.

To do so, what we can do is build prototypes. The early versions may be be low-fidelity (lofi) and are scrappy. The later, high-fidelity (hifi) ones would mimic the functionality of the actual products, and may even appear to work to end users when in reality it could be just be manual effort behind the scenes.

The example given during lecture is the development of a ticketing system. To test the idea out, one could simply get a dude to sit in the "machine" and give out slips of paper.

Anyway, I am explaining all these because this seems like a surprise to those without the same educational background. Long story short, what this startup did is completely normal in the realm of software.

We may have better tools like Figma to simulate browser / mobile frontend experiences, but nothing is stopping us from going back to the basics and doing it this way.