Scalable Artwork

For developers, tessellation greatly improves the efficiency of their content creation pipeline. In describing their motivation for using tessellation, Jason Mitchell of Valve says: “We are interested in the ability to author assets which allow us to scale both up and down. That is, we want to build a model once and be able to scale it up to film quality…Conversely, we want to be able to naturally scale the quality of an asset down to meet the needs of real-time rendering on a given system.” This ability to create a model once and use it across various platforms means shorter development times, and for the PC gamer, the highest possible image quality on their GPU.[/quote]

Is that hype? Scaling down is a concept I'm familiar with, but scaling up? Does that actually work as advertised? Can I find more detail on this somewhere? Seems counterintuitive to me.