In case you missed out or forgot from earlier, those black pillars? They’re keystones. They’re placed around so people without specific implants to interact with holo-tech can use stuff like Orb-Its as well.
Trinity and Luca both have these implants, which are really just a thin membrane sheet that can be harmlessly placed on the skin to summon holo-tech. Obviously, not everyone has or wants these, so the keystones are a necessity for accessibility.