Nearly all statues have a special purpose. The angel, boot, sword, armor, and a couple other statues don’t do anything. The heart/star statues drop hearts and stars, respectively. The mushroom statue produces a small amount of light. The king/queen statues teleport male/female npcs to them, respectively. The rest of the statues serve as enemy spawners, but you get vastly reduced loot, and no coins from them.
I'm nowhere near his level so I'll probably miss some things, but here is the explanation : he's spamming speedruns, so he first reloads the seeded saves (0:01-0:05) he launches a server, because he'll be using the transmutation glitch* (0:06-0:10) he goes into his first world to get sand, needed for the transmutation glitch - and throws his sword cuz why not I guess (0:10-0:12) goes into his second world (0:14-0:16) gets into another one to get iron and a mushroom statue, again, used for the transmutation glitch* (0:17-0:23) gets into the same world, but in multiplayer and mines a pressure plate which he'll be using for the transmutation glitch (0:23-0:26) setting up the transmutation glitch* setup (0:26-0:42) breaks the sand block so that the statue "breaks" (not really, but I won't explain that much further, just go to * if you want the complete explanation of the transmutation glitch) (0:42-0:43) sets up the Campfire Glitch Offsetting* (CGO)(0:43-0:50) updates the mushroom statue to "break it" (again, not going to explain here as it would take too much time) (0:51-0:52) sets up an automatic transmutation setup* (please just check the god damn * part for the explanation) (0:52-0:59) he then proceeds to transmute items, resulting in getting the night's edge ! * for all of the explanations, setups and tutorials, please check out Ethyriel's video : ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-76xkk16qb3k.html