I replied to @mrits because @mrits was presenting virtualenv as replacement for using pyinstaller to manage the installation of non-OS-managed Python versions (which @cowsandmilk was talking about).

I'm unsure how what I said:

> If you want another Python, then you need to install it yourself (somehow) and then point virtualenv at it.

Differs from what you are saying:

> 'virtualenv -p /usr/bin/python3.5 venv'