I admit I do this a lot depending on the strike. Most strikes have enemies that are just thrown at you to slow you down, while others are required to pass through an objective or area. Mainly people do this because they care more about the end objective rewards rather than the loot along the way. For example, the weekly strikes for strange coins, only at the end do you receive the strange coins and that's what I'm more focused on getting. Not the uncommon/rare loot.