Controlling and obtaining all the objectives they can so they can gain a lead that way.
The team is working to objectively play the game. With this extra gold the champions gain item advantages which scale into the team winning a lot of the scenarios where they face the opposing team in a confrontation. By creating that advantage, they can get on top of objectives quickly and give them map pressure and gold advantage. Usually these champions have superior range to its enemy and aims to make enemy go back to base and get their team a number advantage. Poke/siege compositions work around the team moving around the map and destroying objectives with their siege abilities.
