More than that, if there are no unconcealed units for one side, a Melee doesn't develop.A concealed unit is not in melee.. it may move away next turn
Then there's that awkward moment when your opponent rolls a three anyway. @J. R. Tracy alternate universe: you rolled a 2! In some alternate universe alternate you is dancing on the table. Oh, the humanity!That was it is sometimes handy to remain concealed and not attack in CC in your opponent's CCPh so you can simply move away in the next turn.