I think it's a bit of a contested territory because it doesn't violate balance between classes. I recently had some discussions on this on what is considered "clever use". I believe it's not clever use when you use obscure tricks that Blizzard never anticipated that violate the balance between classes (say, switching an ancient tier set before the pull that gives an important dps boost to a class) because we know for a fact Blizzard designs with balance of classes in mind so when the trick violates that it is by definition a bug and even if it's not fixed yet, it is by default on a list of bugs to be fixed. In this case though those people didn't do anything that violates balance.
But, I would put it in a category of "too messy and inconvenient and progress-incompatible [the trash are dead in progress]" for it to be part of the game normally. So it does seem like something the devs would not want to have in the game at all. And it still looks like something that could be by default in the queue of bugs but due to luck of time and resources it's not fixed yet.