Why are there people on the pitwall?

[P38 in workshop]

After the European GP it occurred to me that all the teams have a group of people on the pitwall who can't see much and whose contribution could be just as effective if they were elsewhere.With a solid bank of monitors,they have no view of the track and with the noise of the engines they communicate using headsets.The only man who really needs to be there is the bloke wielding the pit-board and he is only really necessary when the radio gives up.
Is there really a need for the teams to expose the other personnel to the risk of flying debris?Or does a seat on the pitwall indicate a person's elevated status in the team hierarchy?I might be alone in believing the current arrangement is a relic of an age that passed when the switch to electronic communication took place.If there is a sound reason for the current arrangement I am willing to be persuaded of its merits.