My opponent forfeited the previous round, so I'll keep this round simple so he doesn't have to play catch up. MInecraft is 3D, while Terraria is a 2D sidescroller. This offers many advantages in a building, crafting game like these two. MInecraft also has many more options for base material to work with. Finally, Minecraft is the original build/craft game that started the trend. I'd offer more arguments, but I don't want my opponent to fall behind. Hopefully he gets in on the next round.
Now to continue you are right Minecraft is 3D and Terraria is 2D. Minecraft has copied ideas from a lot of games and improve them. Technically minecraft needs to give credits to Terraria because they have copied potions such as invisible potions and many more! Without Terraria minecraft probably wouldn't have those potions they have right now!
The addition of potions in Minecraft had nothing to do with Terraria, as Terraria development didn't start until January of 2011. (1) Notch, the creator of Minecraft, first mentioned to addition of potions in July 2010. (2) As to one owing the other, though, Terraria owes it's very existence to MInecraft, as it started the genre that Terraria is a part of. In addition, Minecraft allows you to choose between 1st and 3rd person, whereas Terraria is only 3rd. You can also build much more complex and impressive structures in Minecraft than you can in Terraria. There are also modpacks for MInecraft that allow many more building and design options. Tekkit and Voltz are two of my favorites, as you can make highly technological creations like nuclear reactors, teleporters, and even a particle accelerator.