Just say no. They should not be on our sites. They have not had any influence with search engines for nearly a decade. Editors should not waste time putting them in and developers should not waste their time by giving them that field.
On most of our content types, they are not on by default, but unfortunately our install profile adds them by default to info page, carousel page, and article page content types. Please go into your currently under production sites and remove "Meta-Keywords" from the content type. DO NOT remove "Meta-Description", those are still important.