"Backing" is a term reserved for a guarantee by another party that something is of value, such as being exchangeable for another asset by that third party, or being insured in some other way (hence being guaranteed).
Such claims as "bitcoin is backed by [insert property/feature unique to bitcoin]" are erroneous. You are providing a property of bitcoin, which may indicate value. Its unique properties don't back it. Its unique properties are it.
This claim is like saying "gold is backed by its unique color". No, it's not. Its unique color is a property of gold, which is why some people attribute value to it. Its color does not "back" it, no matter how you define "backing".
Please stop with these claims of bitcoin being "backed" by anything. Nobody is guaranteeing that bitcoin is worth anything. Nobody is promising your something in exchange for bitcoins. Bitcoin is NOT backed by anything apart from your own personal trust and belief.