>>31210211Well let's put it this way. Normally it's 1.5 so a 90 BP move will do 135 BP damage with STAB.
This means if your opponent resists your STAB (Not double resists), your coverage moves need to have at least 70 BP or more, or else your STAB would just do more damage. (Because 70 x 2= 140)
i.e. if Milotic attacks Swanna with Surf, it will do less damage than Ice Beam, despite the STAB.
STAB being x 2 means that Surf does base 180 damage. Which means that your coverage moves have to have a BP of more than 90 to even matter.
A Surf from a Milotic would do the same amount of damage against an opposing Swanna as would an Ice Beam by that same Milotic.
Running coverage moves would still matter, but suddenly things that rely on Aerial Ace, or whatever, for coverage are better off not even wasting the moveslot.