For example, if your problem is “How to build a better newsletter for existing customers to increase brand loyalty”, you probably don’t need a Design Sprint since you already know the solution of better brand loyalty is a better newsletter. Just create a project and follow the normal product design process. You can still prototype and test with users, but it probably doesn’t require everyone to drop whatever they are working on for a week to figure out the design.
But probably the most valuable benefit of design sprints is that they introduce stakeholders to the importance of validating ideas with real users. Google has orientated the whole week around building a prototype that users find easy to use. That is a valuable lesson for colleagues who can often be more focused on their own agenda, rather than that of the user.