No one wakes up in the morning and says, “Today I’m going to navigate a website and click a button.” People have more important things to do in their lives, like helping their kids, or going on a hot date, or impressing their boss.
Sometimes in the pursuit of real world goals, people need to navigate a website and click a button, but we should never forget that they are doing so for some other reason - and before they make that click - that they must believe their real world goals will be aided.
People click a “buy now” button not because of how easy it was to navigate to find that button, not because the button was so cool looking, but because they believe something.
Sometimes these beliefs happen by reputation, sometimes by a feeling of affinity, sometimes by a feeling of validation, or any number of other impulses. And the way things look is a factor. But different people think and react in different ways.
If we limit ourselves to optimizing navigation, restructuring existing information, and reskinning interfaces - then we limit ourselves to being optimizers only. Just polishing stones. That's not design, but merely decoration.
But if we dig deeper and define the “why” people take an action, instead of just allowing it, then we become the creators of reality. That’s design.