Many Unix systems include Perl by default. This seems like a small thing, but in areas where 3rd-party software is not allowed (security and audit compliance issues), having a Perl interpreter is wonderful.
However, the base install of perl should be used for system maintenance only and not used for general purpose apps as
the base install is just so old (5.8) that its a security hole. Installing a newer version is easy and can be updated independently of the system perl without breaking anything.
They include Perl, but do they include a Perl that is compatible with and has been tested with the code that you're trying to run?