The Plone developers work hard to port the CMS to Python 3 before the support for Python 2 ends. This will be in about 1 and a half year from now. LibreOffice made this step a longer time ago and comes currently with Python 3.5.4. Thus the LibreOffice Python programming environment and connection will get updates and security fixes after the end of 2019 too.
If you use another office suite with Python support you should take a closer look into the supported / delivered version. If it is not Python 3 yet have an eye on alternatives in time.