Basically, the way that these pillows work is that when they are heated, they expand (the plastic will melt away) and fill the void. This maintains the fire rating and prevents fire from spreading and smoke spread is contained.
If the fire puddy or caulk is not completely around the cables or conduit, when the puddy/caulk is heated and expands, there will be a void on the side that the cable or conduit is touching the side of the pipe or sleeve
Steel will deform and twist and this beam will meet little, if any, resistance during a fire. I understand that a pocket of concrete will not keep this beam from dislodging, but it there is a reason for properly pocketing these beams.