Why use a coffee powder press? Coffee common sense

We all know that when using an espresso machine, the brewed hot water has a pressure of about 9 atmospheres (of course, this is not a fixed value, there are also 12 atmospheres or higher), the pressure is very high, and when the water penetrates the coffee cake, the water is inert. What is inert is that water will penetrate through the weakest part of the coffee cake, not through the thickest part. Therefore, if you do not use a coffee press to compact and flatten the coffee (to make the coffee powder density in the powder bowl as uniform as possible), the essence of the coffee will not be extracted, or some parts will be over-extracted.