Dynamic zones help balance the processing of a particular zone across multiple servers based on usage.
In a static setup, an unlimited number of players could end up on the same server causing performance issues in a particular zone. While dynamic will cap the number of players on a server and split the single zone into many to preserve performance.
I’m expecting another 1.5-2 years on the release for this. They’ve announced it’s feature complete and moving to the polish stage. That where they will fix bugs and ensure gameplay functionally feels correct.
Considering the number of chapters they had announced in the roadmap I imagine they have a lot of have to cover.