Although it may be hard to win games playing your guards as PF/C.
At least you can defend on proper positions :) For some games (not the most important) it helps a lot :)
isn't that easy in most times, because someone had to defend the opponent big guys which means you had to play your Bigs on SF/SG/PG which means you screw up your offense even more. One guy like that on the SF spot is possible normally, but he is used best in inside focus you can not play properly with guards on C/PF.