The thing is most of these streamers you are watching are probably on Hardcore Mode. Goblins are not a speed thing at all.In no way are the items dropped from a goblin any different than items dropped from any other mob in that Act. A 5 stack Nephalim Valor killing many packs would easily net more gold and items than goblins. This is just a SAFE strategy used to minimize chance of death while gearing up. Act 1 had the cellar that was normally filled with normal creatures and a goblin or an Elite or Rare pack. Act 2 has a goblin right before you cross the bridge to Alcarnus. Here there can be a few cultists,fallen, and bugs but nothing too scary as well as plenty of areas to trap a goblin against a wall.