Noticed these strange looking balls that may pass for an art installation but imagine maybe temperature control?
Having engineering controls like those balls is generally a good idea and promotes safety.
Unfortunately having a safety indicator be completely unpredictable in appearance (like art) at every different airport, or even every gate at the same airport, not as good of an idea.
But the real answer is that installing art costs more than $0 and 0 seconds, so nobody making the decisions cares.