Newer versions of Elements use the People, Places, Events tags as "system" tags. They are generated semi-automatically using Artifiicial Intelligence. For example, People tags are now generated via face recognition, and Places now uses AI to place geo-tagged files on a map.
The old keyword tags still work (and depending on the version) they may be converted to the newer system tags.
Because, I don't find the Map application useful, I have continued to use my Places keyword tags. (And I'm glad that I did because of several issues with the Maps.)