This hands thing, there's a literal note in the manga about it. The man is an old neuro-scientist, but new brain implants that allow for direct CPU connectivity is something that only young neuro-surgeons are familiar with. For this reason, this man doesn'n't want a man who could be his child to operate direcly on his brain. However, the productivity boost because of the brain implant creates a gap between humans and augmented humans, so this is the solution this man found to work around his refusal to get the brain implant, and so it is clear that it is a fairly bad solution that only exists because of this human "motivation". The two points are some of the major themes that are explored in depth.

I would recommend reading Masamune Shirow's original work (it's only 2 volumes!), as you could argue that the adaptations are merely shells of the original.

On the one hand, the Mamoru Oshii movie version is a 'best of' the cool moments from the original, but it bends the narrative very strongly to express Oshii's POV rather than Shirow's. It's not as bad as in people modernizing Tolkien for example, it's more in line with how Kubrick's version of "A Clockwork Orange" differs from Anthony Burgess' original (which I also recommmend reading). On the other hand, the SAC (Stand Alone Complex) series more closely match Shirow's POV and ambience, it's not as deep, but it's really an impressive feat considering it's all original scenarii, and how entertaining it is.