For all the difficulties I've gone through in learning to turn my thumb green, I don't think I've ever had a time in my life when I actually wanted fake houseplants. The closest I've ever gone is fake aquarium plants and I only did that because the real ones can make almost as much mess in the tank as the fish. I've noticed that people who work in an environment with fake plants eventually seem to stop noticing them. In my own opinion, as soon as a "plant" ceases to be a living thing, it ceases to be a benefit to its surroundings in the same way a real plant can be. Of course, there's probably some study that would be a basis for disagreeing with me.