The long game
Having a purpose means having a driving factor in the pursuit for accomplishing a goal. There is a reason behind what you do and once you finish doing something, the goal is complete and lost.
A goal is such an all encompassing word. It can sometimes mean that doing something every day to builds to or sustains something. Purpose does not only drive checklists, but a system or a way of being. This is what it means to design for the user experience. It’s why it’s important to design for the experience and not just for the feature which a competitor has and you don’t.