This schtuff comes up so frequently I'm gettin' a deja vu vibe. But tally ho...
16:10 was ostensibly to allow movie controls 'n' crap to fit as well. Of course 1.78:1 (16:9) is already narrower than the most common film standards of 1.85 and 2.39 (and older 2.35) but 'tis a compromise with preceding ones (1.33 and 1.66).
Better to axe why 1.78 was pulled out of some brainiac's arse when the existing common 1.85 is so tantalizingly close and would have precluded most of the friggin' composition compromises and subsequent cropping that dim bulbs seem to clamor for so as to fill their precious little so-called wide screen displays <- sarky
It must have seemed a good idea in the late 1980's /early 1990's when such "wide" TV's were truly transitional without much complimentary content. Now, of course, there is a plethora of such video content but it's largely disposable, versus a 100 year film library -half of which is wider and those worth seeing are worth seeing unaltered on the largest screen possible.
So, for PC displays, narrower is better and be glad for 1.6:1 and lower ratios and leave serious movie watching to at least 40" and up TV's (particularly to make up for the narrow format).