Here’s an excerpt from the article:
In many projects, people ramp up slowly, finishing up their old obligations before starting. Without having everyone in the same room and focused, the project takes forever to get to speed.
With a design sprint, everyone starts at the same time with this focused activity on the new project. Even if, the following week, they have to return to their previous project to tie up loose ends, the sprint has given the team this focused burst to start with.
Read the article: Design Sprints: An Ignition System for Innovation Project Teams