Scouts bypass the opponent's spydef pots, thus have a better chance to succeed even if you are a hitter scouting a hansel.
As hansels (and other spy heavy builds) live from their spies (it is their dangerous side), you will want to pin those as effectively as possible and this is done by scouting, especially as a hitter (you'd attack the spy till dtw). As a hansel, you'd assassinate another spy to pin him and once his troops are down (assa dtw), you'd finish his spies off by scouting.