The tags equipment and coffee-machines are certainly different enough to remain separate. By counter-example, I would consider an espresso tamper and a grinder as "equipment" but I couldn't consider tagging as "coffee-machine". Both could in a sense be considered as "machines", and they are for "coffee", I wouldn't consider either a "coffee-machine" as such.
Perhaps the equipment tag is too broad, but I think it's okay as a catch-all. It can include anything that is in coffee-machines, plus lots more. As was pointed out in question and comments, there are other coffee preparation equipment that aren't "machines", but there are already more specific tags for many, such as french-press, moka, and pour-over. There are also more general tags like drip-brew that isn't specific to machine or manual.
I'm happy with the current state of affairs, but if there's something unclear, let's update the tag wiki to be more helpful. If there's something missing, please do feel free to create a new tag!