That depends on the file type. Several version control clients can already detect image files for example and show a visual diff between revisions. There is still a lot of room for improvement and standardization however.
I think this is a big mistake programmers make when trying to create VCS for other industries. A lot other fields with binary files don't care about merge as much. Like electronic design automation: track every part's history and even every module on a board or die layout. But, practically it's difficult to have two people productivly work on the same small piece simultaneously.
[edit] I also think a bunch of the reasons programmers require merge are because code is organized into files. Organization into files is arbitrary and often doesn't correlate particularly well with logical structure.