Having skimmed through the article, I assumed that they hadn't tested the design for mobile devices because it wasn't mentioned. That would be a huge mistake. In today's web design, a mobile-first approach is imperative. This is even more important if you want to showcase your café.
I used the developer tool in Firefox to see how this design would behave on mobile devices. There are huge differences.
Some designs use the screen estate so ineffectively that only the title and a big, boring, generic graphic is shown on a phone. Users have to scroll all the way down to see the content and find what they need. Better designs show the menu, navigation points, and meaningful, aesthetic graphics. Other designs, such as Gemini 3.6, were quite sophisticated but not optimized for traffic and would not load on a 3G connection. However, a simple static website should load instantly on a mobile connection.
That said, even a simple web page has many requirements, so expecting a turnkey, ready-made design if the user is not guiding the process is not realistic. Thus, I believe the best choice nowadays is a model with good design skills that understands and adheres to an iterative design process, offering a good initial design as a starting point but also prompting the user to provide guidance and feedback. As the design process runs through many cycles, the initial cost should be modest. But more importantly, the model should understand its own design, be able to explain its choices so it can converse with the user using concrete elements in a accurate language to guide the process.
IMO, this is still missing from even the frontier models today.