Other than the purely obvious: "It translates Perl to C."; are there any real world uses (a.k.a. hacks) for the Perl compiler's optimized C translation backend, B::CC?
Not really. It means you can convert a (small) Perl script into a (big) C program, which will be much harder for the recipient to reverse engineer. In some paranoid circles, this might be accounted an advantage (for example, if your Perl code is embarrassingly bad and you'd rather conceal that fact from your paying customers). But mostly it is of limited to negative value.