Indeed, what you describe is what I refer to as "blind bale" practice and it does ingrain the anchor points and shot execution without the added complication or temptation of aiming.
I setup a plain bag target in the garage with a 10 to 12 foot shooting lane. I set this up in the garage so I could work this whenever I get a chance and didn't have to worry about the weather or time of day. I focus on drawing to my first anchor point, feeling the pressure of the string on my finger, expand my chest, relax my fingers, and make sure my hand hits the second anchor point after the shot. Then repeat.
My traditional skills are advancing rather nicely at this moment. I can stay within the 8 rings on a 3D Deer target from point blank to 25 yards pretty consistently. Of course there is the occasional string pluck, dropped bow arm, too much back tension, too little back tension, and brain farts that sent my arrows of the mark. But I can now recognize these issues when I do them, make the appropriate corrections, and continue on my tradition archery path.
