While I agree that the shelter is less desirable (mostly on the grounds of if they are going to whine about my EDC Swiss army knife, I wonder what they'll say about some of my other EDC items), there are times when they are the best or even only choice. The four that come to mind real fast are
-Travelling, you don't have your real BoB with you and because your BoL is even further away. You are a refugee
-Chemical or radiation threat, you need to decontaminate.
-You are on foot, and the weather is such that you run a high risk of an exposure injury if you try to overnight in an bushcraft shelter or a tent.
-Due to injury or illness, you are not very mobile. (Me right now- if I tried to walk 15 miles from office to home, I'd have a sock full of blood and be ready to pass out from pain.)

The biggest thing I can think to take into a shelter is an ally- friend, family member, someone who you can shift sleep with and can watch your back.