Knowing what to look for when we are confused or puzzled can help us know how to achieve expert level understanding with far greater efficiency. Complete thoughts and perceptions use more parts of our brain , unlocking more of our abilities, faster and easier. Each are useful for different purposes, and when they coordinate together, parts of our brain coordinate better. Not only in vision does this happen, but in all sensory modalities there is an equivalent of focused, central perception, and side perception. You can not only see what is going on around you without specific focus, you can also hear what is going on around you.
Similar effects occur proprioceptively, etc.
The effects of central, or foveal perception, and peripheral, or global perception, not only occur in all sensory modalities, the effects seem to appear in memories as well as in real-time perception. A lot of attention on one item at a time, perceiving a great deal of detail. Habits are programmed in with focused attention, but aren't automatic until they run in the background, as a peripheral or global background process. Peripheral, or global attention appears to be useful for global awareness, fast and automatic response, such as getting out of the way of a moving object. Also useful for contextual awareness, connections with other contexts, etc.