This article is about a sodium-ion battery which is a different chemistry to the one BYD claimed those results on (that was LFP).

Sodium-ion is exciting because it has the potential to have less degradation over time, much less sensitivity to cold and less reliance on rare earth metals. Could also end up significantly cheaper. However it has struggled to reach the same energy densities and so hasn’t been practical thus far.

This seems like a big step towards it being a practical technology choice for certain models, if it bears out.

"Sodium-ion is exciting because..."

Well it is exciting, but not for the reasons you think. More like a Michael Bay movie exciting...there is nothing practical about this design. Most of the cost will be safety systems designed to prevent the battery from being exciting and even then a crash will likely set them off. Pure Na-ion probably isn't viable and certainly isn't viable in a car. Maybe mixing in some Na into the Li-ion to stretch the small amount of Lithium but even then you are significantly increasing the volatility of the battery.

This isn't a practical step, its an act of desperation from people who don't want to admit that large scale electrification is a dumb idea. We electrified everything that made sense to electrify a half century ago.