Do people use Xavier without flashing Jetpack?

I thought JetPack contained all the OS and the software. I stumbled upon this article from JetsonHacks:
https://www.jetsonhacks.com/2018/05/28/build-opencv-3-4-with-cuda-on-nvidia-jetson-tx2/

What suprised me was under the “Notes” section, I see:

“Most people do NOT have both the JetPack installed and the source built OpenCV on their system. Some people have noted success using both however, check the forums.”

Do people actually somehow use Xavier without flashing and installing Jetpack at all? Or is it that people install Jetpack, and then build OpenCV custom after uninstalling the OpenCV that comes with Jetpack?

You will need to install JetPack to get the support for CUDA. You can then install OpenCV on top. You can choose not to have JetPack install OpenCV through the JetPack Component Manager GUI, under the target section. You can click where it says Install, and instead choose not to install from the drop-down menu.

The statement reads, and means, that people do not generally have the version of OpenCV (OpenCV4Tegra) installed by JetPack, and a custom version of OpenCV installed on the same machine.

JetPack should be used to flash the AGX Xavier. JetPack should be installed on a PC host.