Having worked as a forensic chemist with troopers doing the photography, I'm not going near that statement.The film is not that difficult to use, and remember that professional forensic photographers are -professional- and hopefully know what they are doing!
BUT, IR film can be used to find gunshot residue around a bullet hole in dark clothing. I only saw it done during my internship (those guys were good), but it did work ok. The reason to do it would be to see how far away from the target/victim the muzzle of a gun was. In the lab where I worked, we used paper sensitized with chemicals that would react with the residues, so we didn't try the IR.
IR can also be used in document exams, as mentioned. They have very cool gadgets for that now, though.