I need to consider the context of "puke" compilation. Maybe the user is asking why such a compilation is labeled as "useful" since呕吐 (vomiting) is typically unpleasant. Could it be educational? Like showing how bodies react? Or maybe it's part of a larger series with practical advice, like what to do in a vomiting situation? Alternatively, "useful piece" might be intended sarcastically, implying that the compilation is actually useless, but the user wants an explanation.