If the goal is to develop the shoulder and arm's contribution to pulling, doing so with the scapula relatively fixed appears to generate the most force production and minimal GH joint wear.
In this video, I performed Prone Kettlebell Rows (isometric holds) and progressed in bell size until form significantly diminished.
A focus on "pinching the shoulder blades" - or retracting the scapula - would have disallowed the load I was able to achieve. This would be very clear to those who perform loaded rowing movements on a regular basis. As mentioned above, a fixed scapula appears to generate the most force production.
Whether dragging sleds, playing tug of war, or helping someone from falling off a cliff, most likely do not focus on pinching the shoulder blades. Particularly with heavy loads, the shoulder girdle generally assumes a centrated position and holds itself there with an isometric contraction enabling the remaining segments of the upper extremity to function in phasic contraction. Including the lower extremities (thinking dragging sleds).
This is why yielding isometric holds are being utilized above.
This message should not be confused with never retract or even never retract with pulling.
This brings us to Bat Wings. Dan John states that the aim with his exercise should be indeed to squeeze the shoulder blades together. Often as hard as possible. Those who are familiar will admit the ease of which loads heavier than the exercise intends may be used. Thus, my preference is the use of the FRC principle of End Range Lift-offs and perform Bat Wings in such position.
The aim here is short-range neurological control and force production. Or, increasing the surface area under the left side of the arc of the length-tension relationship curve.
A reminder that requisite mobility precedes. Meaning, adequacy with no external load prior to the use of external load. Elevating the kettlebell/dumbbell - a minimum of 7 inches off the floor facilitates proper Lift-off starting position, but more importantly, prevents the use of heavier loads than would be effective. Bracing and maximal irradiation are a necessity here.
At the end of the day, however, the system - a set of things interconnected - will "produce its own pattern of behaviour over time." (See @drmchivers for more information on Systems Thinking.) And the above, are ways of training its component parts.