It isn't necesarry in terms that the system won't function if it isn't there but some distros have tools that are written in Python.
Anaconda, which is the installer for RHEL, CentOS, Fedora, Oracle Linux, and Scientific Linux, is written in Python as are yum
and dnf
which are the package managers.
portage
, which is the package manager for Gentoo, is also written in Python.