@Mycroft My first computer was a TI-99/4A, but my second was my father's Actrix – https://en.wikipedia.org/wiki/Actrix_%28computer%29 – to which he had added an external amber monochrome monitor that had a composite connection.
When the house TV was in use, I would redirect the NES to that nearby monitor so I could play NES games when taking breaks from doing homework on the Actrix.
Sure, monochrome isn't optimal for games, but I got to see the "secret" overscan areas!