co-witness a a-cog and you have a win/win from 25 to 800 yards. for them that read the instructions and spent adequate range time.
honestly, todays concept of selected targeting goes with higher power optics and weapons. the Gulf Wars made a necessity of fast transitioning from house-to-house to 500 yards.
the term point-blank today is still relevant, though with many combatants wearing armor, the 'good' shot taken during the Viet Nam era, today may not have the same effect.
Can't really co-witness an ACOG. I still run a folder rear BUIS, but it has to stay folded until the ACOG is removed.