If you're talking about binary files, then it has similar limitations to Git and Mercurial, AFAIK. Fossil, git, and Mercurial are not really designed for large binary files.

Otherwise, in Fossil, any text is just another artifact. Wiki pages can be stored as files in the repo ("embedded") and versioned in the same manner as code files (that is, exposed through the same interface), or tracked behind the scenes (in a separate database, IIUC, with a different interface). Tickets and forum entries are also tracked and versioned similarly to non-embedded docs.

Aside from everything being versioned, the visibility of the objects is quite good. The user interface, both command and web, is light-years better than anything Git related.

I highly recommend you check it out. Even if you find it doesn't meet your needs, many of the design decisions are instructive. I find it quite inspiring.