That article does not appear to be making the argument that helmets are worthless, only that they don't protect against concussions.

    The $40 helmet is one of the great success stories of
    the past half-­century. Like seat belts, air bags,
    and smoke detectors, bike helmets save countless
    lives every year. They do a stellar job of preventing
    catastrophic skull fractures, plus dings and scrapes
    from low-hanging tree branches and other common nuisances.

Likewise, US safety standards haven't been updated to reflect more modern medical research on their seriousness.