kevonionia,

I am referring to the Platy 2 liter bottle, not the Platy reservoir. The major distinction between these items is that the reservoir is designed to live inside a pocket in your pack and be accessed at all times through a drinking tube, but the bottle is designed to stand up on its own and if you want a drinking tube you must purchase it as an accessory.

The simpler, more verstaile 2L bottle is cheaper than the more specialized 2L reservoir, because you aren't required to buy a new drinking tube each time you buy one.