How is this different from just figuring it out myself?

You could figure it out yourself, and some people do. Most people don’t — “figure it out yourself” comes with no structure and no deadline, expands to fill all available time, and usually gets postponed for another decade. DYP gives you a framework, a time-boxed process so it doesn’t drag on, and the chance to see how someone else models the thinking so you know what “done” looks like.