Can TUF be used to update offline systems, disconnected from the Internet?

Many of the most important computing systems, such as systems that manage root keys, or tabulate votes in elections, or secure other highly sensitive data, are kept offline and never connected to the Internet.
I'm hoping that TUF could be used for such computers, given some sort of sneakernet polling mechanism and reliable source of the time-of day (e.g. via GPS). But I don't see any discussion of that.
Given that TUF itself relies on having secure systems to manage TUF root keys, it would be helpful to clarify this.

Has it been done? Are there any caveats to keep in mind?