The problem is not "to screw or not to screw" .....

As others have said, the beauty of it is :
- no conflict between the canteen/Nalgene bottle on the belt and the backpack belt
- the convenience of packing the water container in the backpack
- the possibility to sip water more often without stopping (better hydration)

The only downside,in my agenda, is the relative fragility of the blader. But same pb with, let's say, "plastic" mineral bottles. If you fall and crash your pack ...
OTOH, a water bottle in a side pocket has more chance to get crushed, than the blader in its special pocket.

Anyway, I always have a tough aluminium backup bottle along in the backpack.


As you said : try it !!