Be good to mention that another benefit of virtual environments is that pip packages could be installed and used without interfering with what is happening generally on the system
depending on the level of knowledge you're assuming in your audience it might be worth adding a line on how to install pyenv with brew and set Python3 as a global or local version.
Also I think it isn't very clear on this line:
python3 -m venv /path/to/new/virtual/environment
that if you are in the directory where you want to add the environment you can just add the name of the env only.