#####CARDID=14323##### The usefulness of hand traps (monsters that can be activated from the hand during your opponent's turn) is always in a constant ebb and flow. Effect Veiler, D.D. Crow, and this week's card - Maxx "C" - are only as good as they are applicable. If your opponents are never Special Summoning, then Maxx "C" isn't going to be too stellar. Right now though, there are a bunch of reasons to Main Deck Maxx "C", and it's a perfect counter to many common sights.
For example, it's great against HAT, making sure your opponent can't take away all of your cards with a string of Fire and Ice Hand Destructions. Additionally, you can chain Maxx "C" to Artifact Sanctum to compensate for the lost card from Artifact Moralltach. Traptrix Dionaea also gets steamrolled by Maxx "C", as does Call Of The Haunted. Beyond that, Maxx "C" can help you draw into defenses against decks like Lightsworns, Sylvans, and Mythic Dragon Rulers.
Lastly, Maxx "C" can help you draw into your Side Deck cards in games two and three. In Sylvan mirror matches it's crucial to get to that Vanity's Emptiness first, and Maxx "C" gets you there. Just in general though, a card that basically stops your opponent from Special Summoning for the rest of the turn is going to be awesome, and the fact that Maxx "C" comes straight from the hand gives it a giant amount of utility.