As one develops greater self-realization (realization of the 'True Self' as opposed to the 'false self') and wisdom, one of the the first major milestones of this ongoing growth is reaching the state of consciousness often referred to as 'enlightenment'.
So what is the purpose of reaching of enlightenment?
Well, it's not the end-goal itself: As with many goals, it's the 'precessional effect' of the goal which is of real value*.
The precessional effect of self-realization is a state of understanding and wisdom which is to be found far beyond normal human cognitive function. It's a giant leap beyond, in fact so far beyond that it is incomprehensible to describe or experience until one has reached this state.
As self-realized master Eckhardt Tolle says "the finger pointing at the moon is not the same as the moon". The reality is we will not have a full comprehension of this state until we reach it, but that doesn't mean we cannot and should not strive...