There is no such thing as a one finger operation. Both method take a whole hand to operate. The twist method lets the fingers extend comfortably in a natural path along with the hand and arm to allow the user to point the light precisely at the target while keeping the light secured in the hand.
Well, twisty is minimum of 2 fingers, clicky is only ever 1 finger to actuate it. Less fingers holding the light means greater chance of dropping it. If the light is stationary, yes, a single finger can operate a clicky (desk or wall bounce). When holding, the cigar grip means you need a minimum of 3 fingers to actuate a clicky, where any twisty requires 4 minimum.
A twist tailcap means you can't point it where you need it as you turn it on unless you grip the tailcap with your pinky and twist the whole light. The natural position of your hand means the light is turned on when pointed towards your body. Two out of the 3 of the primary modes of actuating a tail switch clicky keeps the light aimed where you need it with no position change.
Both a head twisty vs side clicky both keep the light in the same position, but you have the added option of doing an underhand style activation with your middle finger with a larger Mag style clicky light.
But in the end, using the cigar grip, you can activate a tactical clicky much further away from your body than any sort of twisty, so I don't get how they "have to be kept close to you body when turned on"??