Because the instant I want a dependency, I’m screwed. Half of what I want isn’t on CPAN, and the other half is ten years out of date and requires a compiler toolchain, fifty undocumented build dependencies at nonstandard paths, and five obscure/package-specific environment variables set in order to install. Python? Python either has it in the stdlib or has wheels available for pretty much everything.
Talking super simple stuff here, too: database drivers, markdown formatters, structured data parsers.