The MacBook Pro on which I’m writing this piece needs memory that can keep up with a powerful processor running many programs at once: so it uses a standard called DDR, “double data rate,” which runs at a reasonably high voltage and offers high bandwidth. The processor on my iPhone is less powerful, so it needs less data at any given moment; but voltage matters enormously, since every milliwatt allocated to memory is drained from the battery. So smartphones use LPDDR, “low-power double data rate,” a variant of DDR engineered to operate at lower voltages.

Apple has been using LPDDR in the MacBooks since at least 2015. I remember it was one of the complaint of the 2016-2017 MacBook Pros. They were still using LPDDR3 because LPDDR4 wasn't ready for production yet (despite regular DDR4 being available). The 2018 MacBook Pro's finally switched to LPDDR4.

Maybe author is writing this from an Intel Mac!