I think its just another tool to find players, though i still prefer to use the search options to find guys that fit the roles i want.
I have used player roles when I just can't seem to find someone to my liking, it might kick back a guy who falls JUST under your minumums but other wise is a good player.
But yes, since it doesn't factor in potential you can use it to find players, but not use it to make any other decisions.