Purpose? The purpose for an Oak tree is to produce acorns. The purpose for an acorn is to produce an Oak tree. It doesn’t get any more complicated than this, no matter how hard you try.
In a universe that has no beginning or end, the term “purpose” is rather ambigious, I would think.
I suppose it depends whether you had $5 billion in your checking account or not. If you did, you would not give a shit if you missed a plane. You’d probably have your own personal jet plane, and would have no reason to kill 20 minutes.
If you are one of those ordinary earthlings with no $5 billion in your checking account, then there is purpose for you to find out how come some people can have $5 billion in their checking account and not ever have to wonder how to kill 20 minutes. And why you are not one of such people?
There is no purpose when your mind wonders around what to do for 20 minutes before your scheduled commercial airline departure. However, there is a purpose for you if you set your mind to get $5 billion in your checking account, so that you’d never give a shit about a commercial airliner’s schedule, let alone wondering how to kill 20 minutes before its departure.