I think of the stretching prior to training as a teaching tool more than a training tool I guess. As in for teaching the CNS vs focusing on training the chest, although it will cause the chest to get hit harder.
It is exactly for the type of people you described, those who do not know how to utilize/feel their chest and only feel triceps and delts(btw these stretches also should help you feel anterior delts better). I do not mean they should feel it more than any other muscle, but I do think every raw bencher should be able to feel and fully utilize their chest to get the most out of their bench. I think this regardless of technique.
I also think it is an effective tool regardless of weakness, for instance someone who is weak at lockout, but is not fully utilizing their chest could gain a lot from learning to use their chest for 2 reasons. First being that the chest works through the whole range of motion, not just off the chest. Second being that since the chest can then do more of the work off of the chest it can save triceps and shoulders strength for lockout.
I was more of a triceps and delt bencher before I read a great article by Dan Green, he is a huge proponent of using chest for the bench press.