You both have a point, except yours is a narrow(er) engineering one. OP solved a real-world problem, and actually solved enough of it to be useful to many people, who were thrilled enough to become customers. That is impressive by itself, but what makes it even more impressive is that it is a new niche!

Would adding new features make it easier to create more complex pages? Yes. Would it improve the experience for the users? I doubt it. It's like adding full text editing mode to a chat - technically viable, but takes away the magic - just give me text and emojis and stop there.