[simonh]

How on earth is distributing common Unix tools for MacOS that aren't included in the base OS not "using the underlying UNIX". This is exactly what Unix was designed to enable. Apple understand and values this, which is why they have submitted patches for these projects.

[pjmlp]

Most of the stuff happen to be GNU/Linux replacements for what macOS already provides.

[simonh]

I could quibble with the "Most of" part, most of it is stuff you don't get in MacOS at all, but that aside so what?

This isn't really about alternative ecosystems, it's about complementary ecosystems. There are a lot of people that use MacOS desktops alongside Linux or other Unix machines. For these people having a common set of tools that work the same, so you can use the same command lines and scripts across multiple platforms, is incredibly useful.