I have seen short films at this year's Viennale Film Festival which must have required a huge amount of work, resulting in `experiments' of five minutes' length that were interesting for the filmmakers themselves but almost unbearably annoying for the viewers. The Viennale trailer by Ernie Gehr is exactly the opposite. It must have taken him exactly a minute to film the cloudy sky above him and maybe a couple of days to find and edit the appropriate sound material.
As a film, Carte de Visite is not worth a lot, of course; as the trailer of a film festival it is beautiful because it gives our imagination a lot of space to interpret and to analyze. But if you want, you may as well forget it.