They are comparing this battery to the semi-solid one. The one that is so expensive, they don't even sell it. You can rent it for trips with a car that can swap batteries. That battery costs as the whole car itself. So, this SSB will likely be very expensive and sold in premium cars only.
Advancements in polymer electrolyte technology are allowing higher energy density and lower costs of solid-state batteries. The current theoretical limits are being breached and samples with a 700 Wh/kg energy density are made possible.