I found an older bug report for Debian that sheds a little light on why this behavior is useful: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=308911

    I can understand not changing the behaviour wrt historical
    precedent: I have been told that people used to rely on the
    ignore-dot mechanism to disable things (e.g. mv foo foo.disabled).

At the end of the report, you can see they added the --regex flag to allow for user-defined filename validation.