As a leader, you want a productive team, so it only makes sense to reinforce timeliness and help team members steer clear of bad work habits like procrastination.
Procrastination eats away at productivity of the person who is procrastinating. More than that, it adds stress — stress to the procrastinator as well as to the rest of the team, who must struggle to take up the slack for missed deadlines.
It also leads to negative emotions that erode teamwork. The procrastinator carries around a load of guilt for not being timely, and others on the team feel resentment for having to make up for someone else dropping the ball.
