I am a clear proponent of as much natural environment for living creatures as possible.
For millions of years, chameleons evolved on their natural environment and build close bonds with it. There is no reason for using fake plants and vines in the cages, they are harmful and unnatural.
Live chameleons on live plants!
Risks of fake plants:
Easy contamination with excrements and dust
Easy soaked with water for long time
Source of bacteria and fungi permanently available to infect
If eaten, potentially toxic
Containing toxic substances that sublime into the air and water sprayed on, thus source of intoxication
If eaten, can block intestines and cause death
If soaked with water or wet, can cause over-hydration of soles and problems with shedding and infections, especially fungal
Potentially sharp and spiky or unnatural textures, thus danger of injuries
If insolated with a heat source or UV, can expel toxic substances
If by accident got too close to heat source, can melt, deform, burn and expel toxic substances
Have no nutritional value but can be misidentified as food source
If misidentified as food source, can cause long chewing with possibility to hurt mouth and cause mouth rot
If chewed by insects and ingested or becoming part of the dust, severely harmful
Fake vines cause eye infections by falling off small particles entering the conjunctive sac while the chameleons rib their eyes off them
No self-cleaning properties
No antibacterial nor anti-fungal properties
Questionable esthetic value
No bioindicator-function (if the cage microclimate is OK for plants, it is more likely Ok for animals, on contrary, where plants die consistently, something is definitely wrong with the environment)
No positive impact on environment management esp. humidity
No natural regulation of gases available in the environment in daily rhythm (living plants emitting O2 at daytime and CO2 at night time, which is natural and helps to keep daily rhythm, correct sleep etc)
Different heat-absorption properties than living plants
Fake plants are good for plastic chameleons only...