Some of them allow you to choose, I don't think many distros have the openbsd-netcat installed as default choice though.

I run Manjaro on my laptop and we have gnu-netcat as default with the choice of installing openbsd-netcat instead. On my Debian servers I have just "nc" which, if I'm not wrong, is the standard netcat (non-gnu/non-bsd).

Lots of network devices will not have nc, wget, curl, etc. Which makes exploiting cmd injection annoying, you often have to drop a bin in chunks using hex-formatted echo.

OpenBSD is a type of UNIX operating system. The OpenBSD project focuses on security. Www.openbsd.org