• Because perl is interpreted, as opposed to compiled, the development time is cut down as the compliation step is non-existent. (Do note, of course, that perl can be compiled to native executables to speed things up once scripts are debugged completely).
• The perl code will remain portable across platforms if that so happens to the case. You'd have to recompile C scripts and account for any vendor differences with C.
• Perl's much less prone to 'buffer overflow errors' compared to C, given that you don't have direct access to memory. You still need to run with strict, -w, and -T, but a lot of security headaches can be removed in this aspect.

Update: as pointed out to me, perlcc'ing a perl script does not gain any benefits during runtime compared to intepreting that script, so the second comment on the first point is null & void. However, the fact that avoiding the compilation step to just test and debug code is a definite benefit.