Design intent doesn't get lost in translation
On a design-only project, the studio hands off detailed drawings to a contractor who wasn't in the room when the decisions were made. The cabinet hardware spacing, the way the tile pattern wraps a corner, the exact alignment of the door frame to the kitchen island — these are decisions that re-litigate at the build phase, often badly. In a design-build engagement, the studio that drew the elevation also coordinates the build. The decisions hold.