It's not an answer for why they didn't go the extra step, but if you only want to know if a unit is within/outside X yards, taking the square root of the return isn't necessary. Maybe they decided to skip the last step for efficiency?
In
this addon it just checks distance<22500 (150 yards) or 75000 (500 yards). edit: and apparently there may be a need to get a squared return for retards like me who can't work a calculator. 500^2 is 250000.