This guy seems to think it’s practically make or break for some players.
Why are these minor differences that big a deal?
Becuase they aren’t minor difference. For obvious reasons your standing reach is very important. Height is a big part of that, but wingspan is also important and can be the make or break number for a lot of guys. For example, Shelden Williams and Elton Brand are both 6’8 1/2". Brand has ridiculously long arms, while Williams is a T-rex. As a result Brand can reach 9’1 1/2" while Williams can only reach 8’8". Those 5 1/2" is going to be the difference between Brand being a great player, and Williams being a flop.
For comparison’s sake the reaches for the positions are generally as follows:
C: 9’2"+
PF: 8’11"-9’1"
SF: 8’8"-8’11"
SG: 8’5"-8’8"
PG:8’5" and below