It is all about cognitive load

The human working memory allows us to work with 7 items (plus or minus two). This is the capacity of short term memory and when we program our thinking is all there, in the short term memory.

What happens if you fill that memory with design patterns and langauge sintax? You forget the problem you are solving.

The first thing I experienced when I stated to work with UD was a great relief for my mind. I was able to think about all interfaces and queries I felt completly free. No more MVC, no more tree file open to change a feature, everything was close to hand. Yes I know, SQL was still there and json syntax too. But it was so much less to handle with my brain.

I was able to think more about the (human) client, the problem, and I was so quick. I was able to redesign the application in a matter of days.

This is what I think is the main point of using a structure like UD, it helps you the focus and think about the problem you are solving for your client.