When your commander is a creature, opponents can hit it with removal, like Swords to Plowshares, and board wipes cease to offer the protection they usually do
If another effect (or effects) modifies how much damage your Giant source would dealby preventing some of it, for examplethe player being dealt damage or the controller of the permanent being dealt damage chooses the order in which any such effects (including Calamity Bearer's) apply
Where this card really starts to take off, however, is that it can also function as a win condition
no fair
Its about 75% committed to being an otter deck (why are there three copies of Waterspout Warden here?), and the rares arent half-bad, with the exclusive Bria, Riptide Rogue being an actual house of a card
Maybe dont go emptying your hand, eh