Question

What is the purpose of setting a deadline for a goal

Answer 1

Deadlines for goals are have several benefits.
1) essential for completing tasks in a timely manner
2) deadlines provide structure; one might have step one to be done in 2 weeks before being able to move to step two.
3) deadlines help with keeping the focus on the end.
4) deadlines help keep costs down; as well as procrastination & anxiety.

These are just a few but I think you'll get the message.

Answer 2

The purpose is so you can accolmplish your goal