The past month or so, something has been on the back of my mind, that I can't quite put my finger on.

It has to do with balance, and the purpose of it.

an example of a runout

bttn raises, hero defends K9o on BB, and the flop comes 9c5s2s, the flop goes bet/call
the turn is a 5 and it checks thru
the river is a Qx.

Now, My thinking is that we want to have a large bet size here on average if we are to have a balanced range. But what is this achieving? the bigger sizing allows us to have more bluffs. So, the purpose of the polarized sizing is to create a scenario that allows us to profitably play more hands, because we can bluff more with a balanced range?

I'm honestly not even entirely sure if this is the question I'm trying to ask. Just something I feel im on the edge of learning/misunderstanding.