When i see piper getting cover and fire (protecting their bodie) and just showing head and gun, i am asking why we cannot do like them...

The enemies and followers "getting cover" system is like in Mass Effect 3, and any modern games..

So why can't we do the same while the npc and enemies can do it ?

Why can't we have access to a good getting cover function (Press R3/L3 or any other key) against a wall, desktop, corner to get in cover...

we do have it, but only in 1st person. Hold your aim button to peak out from behind objects.

Yeah, if you set up behind a corner or some cover and your gun lowers, it means you can aim from cover in that position.

Oh yeahhhh, you are right

Wow. Learn something new every day, thanks