Although it may be used as a single-card addition to SOME decks (I dunno which ones... I suppose something that has low-attack creatures, but then again, momentum is just plain better...)
After seeing the card I instantaneously thought about Pharaohs+Scarabs (Fractal Scarabs also works). Of course, the combo only works if you already managed to set up a field full of scarabs, so in most cases you win simply through scarab's damage. Catapult can work as an emergency card for situations like phase shield stall, diamond shield, gravity shield, emerald shield, permafrost and the like. In this case, catapult is much better than momentum for 3 reasons:
- Lobo/Rewind etc. can't counter it. (PC can, but Pharaoh decks usually take Procrastinations, Eternities and SoGs, so it's no big deal)
- In unupped decks the combo works equally well (unupped scarabs are 2/N, upped 3/N)
- It generally results in higher damage gain/card.
Generally with a field half-full, it's ~9 damage per 2
With a full field, it's ~15 damage per 2
Not much, but as I said, enough to beat a stall deck, especially if you have SoGs to give you some Time.