It is a function of personal preference and training. Our ROE used to require no round in the chamber, and the Israeli Military still train to that in sidearms. Generally the theory is based on safety arguments either you not having an accidental discharge, or someone taking your weapon away and not knowing they have to rack it first. If you train to that standard, and train to racking with one hand, both strong hand and weak hand. OK, and yes it can be done.
Some folks make a fast draw argument against empty chamber. As a CCW to me that is moot argument if your situational awareness fails to the point it comes down to a fast draw, you already made serious mistakes in your situation management CCW is not a Cop, you do not HAVE to confront anyone. But with training you can draw chamber and fire in under 1 sec if that is your carry choice; with 2 hands you draw and slap the top of the slide at the rear sight pushing under the off hand, pushing the weapon forward racking the slide as you present. With one hand you need a flap holster or a stout belt, catching the rear sight on them and using that to rack. In a pinch jeans pockets can be used as well. And I do train to those techniques, but they are not my "ready" condition
That said as a CCW I do carry one in the chamber, but I don't use striker fired weapons, so a mechanical act is required to fire. For me if I want to carry now without a round in the chamber or under the hammer, I would carry a revolver.
But that is just my 2cents and a generous valuation at that