Beyond looking realistic, Digital Twins also need to be “simulation-ready”, which means they need to function like their real-world counterparts. They need to carry information and exhibit properties tied to their ontology and physics (and more). In every way possible, they must be grounded in real-world data. And this data structure needs to be accessible and interoperable. A Digital Twin can be viewed as an encapsulation of all the relevant data that the utilization of that Digital Twin may require.
How is all that different from a standard 3D asset created by an artist or downloaded from a marketplace? A good 3D asset is still only a 3D mesh with a realistic texture. It carries no information regarding size, mass, stiffness, etc., — all the vital information and properties required for effective simulation.