relying on mech also gives mafia the benefit of seeing what actions a specific user will use if they're town (or indie in flower's case)
the biggest thing it shows and helps with is sniffing out character roles, abilities that mafia can devise a plan to counter, or worse, kill
not to mention, vague abilities and WUs can easily be used as a way to link specific actions to a player to set up the illusion of being scum by mafia themselves
so all this out in the open isn't something we should depend on in its entirety
a mixture of mechanics and weird behavior from people is needed to win, not either or