Would be not so easy to determine what type of defense your opponent pick unless you know him already into deep. It looks like interesting factor to me which could be used to this. This is the only argument, but could be worth.
Assume that defensive skills are only one which are taken into consideration during calculation. (if you switch defensive matchup)
So if you use your SG to defend opponents SF for a tactical reasons, his other skills will not take any effect, just the defense, but only one who could figure out this confusion would be your actual opponent after the match, the next one could be suprised by defensive ability of your SF like the last one.
So it is not any useles-only-providing-information thing, or only help during training juniors on unusual positions, therefore I think that should be taken into consideration to show that only to the teams which are involved.