Computer models (GIS, CAD, and various database technologies) have been in widespread use in urban planning for over 3 decades now. The core idea of a "digital twin" is not new, IMO it's merely a buzzword for a 3D map. Granted there have been huge advances in Lidar and remote sensing technology so the computer models are now richer with data and provide a more realistic interactive experience.

It's not clear how important the interactive experience is to real actual urban planning concerns. For most use cases, you need a robust data model and process automation - the fancy 3D visuals look cool but the bulk of the real work is still plain old applied database management.