How important Poses are??

I’m working on a personal project and I have set my player’s animation blueprint without a single Pose (only the cached poses from state machine). I wonder if I can make it look better using them but I don’t really understand how they work or what is they main use.

Can anyone shed light on this? Are they useful somehow in blendspaces or state transitions or something very basic that I should know but I don’t??

Thanks