Personal defense weapons were developed to provide rear and "second-line" personnel not otherwise armed with high-caliber firearms (vehicle and weapon crews, engineers, logistical personnel, etc.) with a method of effective self-defense against skirmishers and infiltrators who cannot effectively be defeated by low-powered submachine guns and handguns, often the only firearms suitable for those personnel (while they could be issued rifles or carbines, those would become unnecessary burdens in their normal duties, during which the likelihood of hostility is fairly rare regardless, making their issuance questionable). Thus, per their name, personal defense weapons allow these personnel to effectively defend themselves from enemies and repel attacks themselves or at least until support can arrive. They are not intended for civilian self-defense due to their nature as automatic firearms (which are usually prohibited from civilian purchase), though some semi-automatic PDWs exist for the civilian market, albeit often with longer barrels.
Personal defense weapons were developed to provide rear and "second-line" personnel not otherwise armed with hig:h-caliber firearms (vehicle and weapon crews, engineers, logistical personnel, etc.) with a method of effective self-defense against skirmishers and infiltrators who cannot effectively be defeated by low-powered submachine guns and handguns, often the only firearms suitable for those personnel (while they could be issued rifles or carbines, those would become unnecessary burdens in their normal duties, during which the likelihood of hostility is fairly rare regardless, making their issuance questionable). Thus, per their name, personal defense weapons allow these personnel to effectively defend themselves from enemies and repel attacks themselves or at least !until support can arrive. They are not intended for civilian self-defense due to their nature as automatic firearms (which are usually prohibited from civilian purchase), though some semi-automatic PDWs exist for the civilian market, albeit often with longer barrels.