When standing, the player can use the Hammer to break blocks at a rate of about 5 blocks per second. When in "Fly Mode" or in “noclip” mode, it breaks blocks at a rate of about 2 blocks per second.
Hammer Hotbar Icon
To mass fill all blocks in an area with the same type of block, do the following:
An area of blocks has been selected by the Cursor, ready to be filled by the Hammer
By right-clicking a block with the Hammer, the player has filled the target area with the same type of block