Guarding thugs

[PaoloZ]

I have a little doubt about hardly paid troops set on Guard commander order. It seems they only sit around their chief taking blows and arrows. Like a living (or maybe non-living) shield.
Is this a wrong feeling?
I have been in a situation where the intervention of guarding elite troops would have turned the tide of battle but I watched helplessly as they stood there without returning blows...

If this troop shield effect is true would it be better to have cannon fodder guard the commander? Why pay a lot for elite troops if they only sit around?