This rejoinder points out that the psychometric properties of trait domains have, at least at present, limited clinical relevance to treatment choice for the most severe personality disorders. Since patients with PDs are often misunderstood and mistreated, it is important to retain classifications that usefully guide treatment methods. The author also points out that the ICD-11 system for classifying personality disorders remains provisional, and does not have enough research behind it to solve the complex problems of PD classification. Since borderline personality disorder as a category can guide the choice of effective therapy, it is fortunate that it has been retained in ICD-11.