Well not only that...
You pass out the tables, melee weapon to the meat shield, bow to the archer, etc.
After a while, the player who always plays archers knows all the modifiers for visibility, cover, concealment, range, angle, windage, etc. better than you do, and when anyone has anything happening at range he's helping you referee the mods. Same goes with the meat shield for anything happening at melee range. Same goes for the mage with anything magical. Given time, the GM only has to GM the scenario logic, everybody helps keep track of the game mechanics.