The advantage is this lets you see what something would look like in a few minutes without needing to learn the thing (saves you 2.5 hours) the disadvantage is when you try to add new features or build a new site you haven’t learned anything. The 2.5 hours is an investment in the skill.
Another interesting thing to point out is how the UI pattern is off in your example. Do you see how “selected” category is in the same multi selection as the actual menu items whereas the normal UI pattern would be to have a Cart or something on the page. This is the issue that I have been running into with these Generative UI approaches is this stuff happens constantly and in very strange ways.