I think Greaves might be a trap...

Moggcatcher costs plus to activate. So assuming Greaves is already on the table, you'd need 7 mana to play and activate Moggcatcher.
Jitte is the better equipment based on the creature density and ability to control a game.

In defense of Magus...
Against Miracles, it shuts off fetchlands which makes their cantrips worse.
Against D&T, assuming 8 Moon effects, I'd actually recommend upping your # of maindeck Chainwhirlers. That card wrecks D&T. I'm currently playing 4. (2 Cratermaker)