Bitcoin is unique to me because it is temper proof and time stamped, I will also say because it has no physical representation yet it has much more value than fiat and it has become the biggest inflation resistant asset and currency of all time. The uniqueness of Bitcoin is so much that it affects even fiat to a large extent.
Are you referring to tamper proof? I find Bitcoin unique because of its ability to rebound or recover after crashes and recording new ATH every 4 year cycle. The transparency, decentralization, isn't that unique since many other crypto has also that feature, if ever, aside from what I stated, I believe security can be the major reason why Bitcoin is unique.