Tjspiel covered it pretty well. I should add that given the price of garage space or sq footage for real estate or apt rentals in NYC an owner of a bakfiets will be paying an exorbitant price for the privilege of keeping a bike with the footprint of a bakfiets conveniently available for daily or frequent use in transporting the kids to school or any other typical cargo hauling tasks.

Hype about the practicality/value of bakfiets and similar expensive esoteric dedicated cargo hauling bicycles for transporting children in the U.S. is just that - media hype. There are more practical methods but perhaps not as trendy or appealing to New Age parents with cash to spare.

I can only guess what posters must be thinking when recommending a bakfiet as a solution to the problem presented by the mother in the OP.