Susanoo's main gimmick is his ability to break through defenses, which are only usually available in PVP if someone screws the pooch on the enemy side by deciding 'hey red is a good card to play on this snow right'. However, when he does, he gains a huge multiplier for a single attack, which multiplied by his fantastic attack stat, equals to someone's face getting melted. This is also incredibly useful for annoying PVE bosses who have say, a huge amount of counters on their face, as that is the default mode for PVE counter. Even without a defense to break, Susanoo's stats just simply means he can deal a lot of damage. Which is okay.
However, his subskill is almost entirely worthless and his stats are kinda the definition of glass cannon to make his killer attack, and he exists in one of the best attacking colors in the game. His super fusion is mostly without merit, as well.
Sadly, this means Susanoo is not a very priority card, but luckily still a very good slot, especially in a sword week in colosseum, or during an event that requires defense clearing.