Gun control advocates often ask why anybody needs a magazine that holds more than 10 rounds. Deciding legality based on need is a common trap authoritarians fall into. Due to the lack of specialized knowledge one cannot know what another person needs. For example, as Uncle pointed out people being attacked by multiple assailants would benefit from having standard capacity magazines:
Bullets flew during a deadly home invasion robbery as a homeowner traded shots with several suspects.
A suspect was caught and cuffed in connection with the deadly home invasion robbery. Police say the homeowner was rushed to the hospital after trading shots with several suspects and killing one of them.
Advocates of gun control claim that forcing a shooter to reload more often gives somebody else more windows to stop him. That logic works both ways. If a homeowner is being attacked by multiple assailants they leave themselves vulnerable more often if they have 10 round magazines. Once again we see something advocated by gun control supporters working against the lawful.