This extension allows users to read Chinese as it written in Taiwan and Hong Kong whilst learning Chinese in Duolingo. From an an etymological standpoint, many simplified characters no longer make sense and have crucial strokes removed from them.
If you're interested in reading any Chinese literature published before the 1950s it will be most advantageous to learn the traditional characters. Also, it is easier to read simplified if one has learned traditional Chinese, than the reverse.
The extension is installable at https://chrome.google.com/webstore/detail/clnnjdojceobnkhkocigpboialomopfk/