There's a dedicated button for almost everything (except for browsing samples, which is something that it would be impossible to have dedicated buttons for).
The great thing about Push is that you sort of make your own UI. If you put an instrument rack on a track then you assign your own macro knobs for whatever you want. It's only if you need to access the devices within that that you need to start navigating around using the (dedicated) buttons.
Without the on screen menu the function of the buttons/knobs across the top are not clear.
As opposed to having one button/knob per function.