Hoiks are kept in because they're useful, don't interfere with regular gameplay, and can't be exploited to break the game or cheat like, say, item duplication can. The devs have specifically stated that they've gone out of their way to keep hoiks in the game. The dirt rod glitch was not dissimilar in theory, though its usefulness was much lower than something like hoiks, since falling sand has a pretty low damage value so you're only really getting a decent earlygame weapon out of it. One that requires a bunch of setup time of building a stack of sand on top of a dirt block every time you want to use it, and has the issue that you need to keep holding left click to keep using it, otherwise you'll drop it and have to do said setup over again. It was just fun to mess around with. Really, the bigger issue is the question of how difficult it would be to program back in, given the fact that Terraria has a notoriously finicky engine.
