As individuals and as organizations, we are only capable of paying attention to a teensy tiny little bit of the world at any one time.
The bit of the world that receives our attention is improved, and our performance with respect to it is (generally) solid, but we always forget that it is only a tiny little piece of the puzzle. Errors and omissions tend to happen where our attention is not directed, at the boundaries between individual and team responsibilities, for example, or where the play is fast moving and priorities quickly shifting.
The primary purpose of automation is to help us correct and compensate for that deficiency; to allow us to be more organized and systematic, without compromising our ability to be mentally agile and flexible.
It is important to note that there are other aspects of automation and tooling that exacerbate, rather than compensate for, this deficiency. In particular, as Fred Brooks notes in his spookily prescient "No Silver Bullet" essay:
... the screens of today are too small, in pixels, to show both the scope and the resolution of any seriously detailed software diagram. The so-called "desktop metaphor" of today's workstation is instead an "airplane-seat" metaphor. Anyone who has shuffled a lap full of papers while seated between two portly passengers will recognize the difference--one can see only a very few things at once. The true desktop provides overview of, and random access to, a score of pages. Moreover, when fits of creativity run strong, more than one programmer or writer has been known to abandon the desktop for the more spacious floor. The hardware technology will have to advance quite substantially before the scope of our scopes is sufficient for the software-design task...
(This is why a couple of big 30" monitors is still not enough...)