Kevin,
Lest not forget that a sniper-teams is also a Forward-observer,target designator and Forward air controller in addition to the fire-team mission.

When we set-up,we became more than just a "bolt-gun,sidearm,grenades equipped",we would cause entire units to "hunker-down" from the accurate fire instead of spraying about with a 30 round AK/M-62!
We had are escape routes planned and were also equipped with M14,M16 and M18 landmines.

Why do you think that we are known as "force-multipliers"?

One team can harass and harry a unit(squad,platoon,company)and delay or alter their progress.
By causing them to have to alter their main orders and go to "plan-B" is a win for us!

In a urban zone a team is as or more effective as heavy weapons are not as effective and most commanders do not want armor in a urban setting as they are easier to kill with their main guns not as effective.

Mike