Regardless of which type of containers it fits on or doesnt fit on does not change the fact they can be a serious PITA to fill. A standard soda bottle isn't going to fill any easier than the sawyer bladder in 1" of water. Where a pump will work no problem.
Luckily for everyone there are many different water treatment methods
Vecto Water Container, 28 mm, Orange – Cnoc Outdoors
A 7" diameter opening works pretty damn easy. Hell of a lot faster than my partner's katydyn pump.