Does stretching in the morning help or is it a waste of time?

It is pleasant and mildly useful, but not for the reasons usually given. Morning stiffness is largely normal and resolves with movement regardless of stretching. What a short morning routine does provide is a gentle transition into activity, some improvement in range of motion over time if held consistently, and for many people a reliable habit anchor. What it does not do is prevent injury or 'wake up the metabolism'. If you want a higher return for the same ten minutes, movement that gets your heart rate up slightly plus daylight exposure does more.