I personally value a lot not having to install stuff by hand on my system, hoping for the version of the said dependencies in my OS package manager end up working with the software I want to use. Using dependencies managed by the language dependency manager removes 99% of the dependency hassle.
(Yes, I know I could install an complete second distro in docker and run the software there. But I won't, thank you).
I see the confusion, I tweaked the README to remove that claim. But I indeed meant "no external dependencies like postgres/redis..".