Remember that China Airlines Boeing 737 that burst into flames after landing last week?
According to the 8/28 addition of the Wall Street Journal "Investigators believe that mechanics may have failed to replace a washer during a routine inspection of the bolt assembly just weeks earlier, permitting the bolt to come loose, punch through the front edge of the plane's fuel tank and create a major leak."
A washer. Responsible for a major airline fire.
Details matter. Someone in the organization has to have done the pedantic verification of each and every possible aspect, in order to know that the product will work as intended.
Now the level of performance necessary to win in the marketplace depends on the product and the current business conditions; translation, the affects of product failure in the marketplace depend. So, if the product doesn't work as intended it may or may not matter.
Obviously designing airplanes is much different than designing decorative pots. But, if you want to know every aspect of product performance, that is the details, then you need to do the work.