Yeah, I guess that's also to show how everything in the world he describes is interchangeable, bland and without any real meaning. Everything gets blurred because everything in Bateman's microcosm basically looks/tastes/sounds the same, and no one really cares. All the human interactions are obviously surface level as well.
I mean it’s also the main device to show how unreliable the narrative is and confuse what’s real with what’s fantasy/delusion