Setting goals using Work Breakdown Structure, a Gantt chart, or any other project planning methodology is a good practice. The team can focus on these goals and make decisions based on them. That said, you should avoid unclear goals and objectives as they can easily turn project planning from a structured and well-organized process to a chaotic list of goals and milestones you cannot control.
Compare two goals: 1. Increase traffic and 2. The organic traffic of the site must be 1,500 visitors per day.
One is clear and measurable, one isn’t.
That is why SMART goals appear on the project planning horizon. A product manager usually formulates sprint goals in anticipation of goal and goal-detail sharing. SMART goals keep everyone focused and on the same page.