If you can bring yourself to get past the SDx marketing bandwagon, the paper covers multi-battery and multi-chemistry systems. Laptops aren't the obvious use-case for this. Given that Tesla is involved, they're thinking more along the lines of cars and home/office energy storage, where you have a large and diverse set of batteries to manage, and interesting real-time pressures you just don't see in a laptop.

BMS in a laptop mostly just has to keep the battery safe and avoid unnecessary charge/discharge cycles. In a more complex system trying to salvage every joule of energy and maximize lifespan of each cell, the fact that batteries are less efficient to charge (or discharge) the closer they are to full (or empty) might be taken into account when deciding which to charge/discharge (for example).

A car might dump sudden regenerative braking power into high-C batteries if the main batteries can't take that charge at a given instant.

Satellites often use exotic batteries able to fully charge and discharge 10 times a day for decades at a time, but these have enormous self-discharge rates measured in days. Every chemistry has a unique set of compromises. There is plenty of room for smarter BMS in consumer systems that manage complex battery storage arrays responding to thermal, aging, cycle count, charge and load pressures more intelligently.