Just watch the top of the pitcher's head. Compare the height to some adjacent object and then watch how much it dips as he strides. Time spent going up or down is time NOT spent moving towards the target. It moves the eyes which are supposed to be focusing on the target, it might affect balance and posture, and it makes you slower to the plate. Furthermore, for all the guys that believe in tilting the shoulders to get a higher arm slot and throw with more angle, it lowers the release point and reduces that angle. I'd think those guys would be more concerned about this than I am.
I'm not sure if you actually meant "pointing" the glove at the target. House doesn't recommend pointing the glove at the target. He only recommends getting it out front and leaving it there. The arms need to he in an opposite and equal position at foot strike and then the torso moves to the glove. The glove can be pointed at the target, tucked under, hooked to the side, what ever.
Regardless, it's not about pointing the glove at the target - it's about not sweeping because that can lead to problems with shoulder rotation. The fact that the pitcher has time to sweep the glove means he is not getting to foot strike as quickly as he should.
Well, these video clips represent contrived situations. Maybe he didn't open up too early in these two video clips because he knew the camera was on him. But pitching is all about consistency. When he's not performing for the camera and he's in the heat of competetion, will he still stay closed? Maybe. Maybe not. I'd prefer to increase his chances and, to me, eliminating the sweep is appropriate.
But is there not an effect on the release point? Again, what are the pitcher's chances of getting a consistent release point with the late movement of the head?
The head movement usually causes shoulder movement. Pro pitchers have gotten to where this movement is fairly consistent. With the young pitchers I work with, it's tough for them to have this kind of movement and still be consistent. So I opt for eliminating the movement. OF course, I don't teach tilting the shoulders to acquire some desired arm slot. I teach throwing with the arm slot that feels the most natural when not tilting the head and shoulders. Different stroke for different folks, I guess.