Doesn't really make much sense, in-universe. It's supposed to release his inhibitions, and basically make him do whatever he wants, right? Which, in Smallville, turns the whiny angst up to 11, and makes him a super-dick.
Actual SUPERMAN, however, isn't exactly portrayed as a guy fighting his inner demons for control. Nor is he Spock wrestling with emotions. The guy is just a boy scout, super-do-good'er, so releasing his inhibitions really shouldn't make much difference, since he's a mid-western, mild-mannered, aw shucks kinda guy anyway...
Batman clearly has a few inner demons, so letting HIM cut wild would result in a blood bath.
