For some context the article doesn’t mention: this is a special case of the painter’s algorithm, which handles occlusion by drawing back-to-front. A limitation, as the article does note, is that you have to special-case cycles somehow, because the basic algorithm doesn’t work if there is no strict back-to-front order. Another limitation is that when you have a lot of things in a scene, it can be inefficient, because you end up drawing a lot of things that will ultimately not be visible because you later draw over them (this is less an issue with isometric views than in general 3d graphics though). Once you get to the point of handling various special cases, things like splitting the boxes to ensure there aren’t cycles, etc. may get more complex than it’s worth, in which case you might consider an alternative algorithm, z-buffering.