Also, if this is for an educational market, another answer might be simplicity. Kids and teachers and parents likely didn't want to have to shell out multiple times for lost dongles.
Also the article isn't arguing that the laptop shouldn't have any USB-A ports, just that the charging cable should be USB-C rather than a proprietary cable.
Having to go back to the bad old days of researching all kinds of cables and adapters and monitors and crap to figure out whether some combination of them will maybe do what we need them to is a giant step backwards. Doing anything with the new MBPs and external hardware starts with a frustrating dongle/cable search, as well. The benefits of USBC are, so far, non-existent—it has been an entirely negative experience.
Break-away magnetic charger connections are huge if you're going to be issuing them to students. There goes a big chunk of your out-of-commission broken laptops, because somebody tripped over the cord.