Another who prefers the small CR123s and will not buy a built-in. Chose Rattlers partly on the basis of the Adder's built-ins that add weight and have potential to cause havoc if goes bad - even if rare. I don't keep batteries in anything except Aimpoints.
More frequent battery changes? Don't care. Batteries draw down faster in the cold - small, large, EV-size, whatever. Bring enough of whatever battery you need.
Nice to have options tho. No right or wrong to this.
