I am able to easily check whether or not I have forgotten something inside!
I work for a media production company and often travel by airplane to my locations.
I am always worried that I might leave something behind. However, because there are mirrors installed inside the stowage bins on my airplane I am able to easily check whether or not I have forgotten something inside. I think these mirrors inside the bins are a great idea and make me feel more comfortable knowing that I will never forget anything behind!