Maybe I should specify, that the weapon should not be completely lowered (as with using the weapon lower function), but just slightly lowered so that it would not be pointed directly at whatever the player is looking at.
If I where to have to raise and lower my weapon manually to look at my teammates it would become tiresome and the clunky nature of raising and lowering your weapon (especially when crouched) could get you killed.
Your gun is still "up" just not aimed directly until either fired or aimed down the sights.
It's just a small feature that could make a big difference in terms of immersion.