Is Decentralized Identity/Self-Sovereign Identity (SSI) the killer application for blockchain/DLT?

Hi friends at w3c and Indy,

Is Decentralized Identity/Self-Sovereign Identity (SSI) the killer
application for blockchain/DLT?

Can the idea Decentralized Identity/Self-Sovereign Identity (SSI) be exist
without a merkle tree based distributed ledger with BFT algorithm? Any
distributed database could be the storage tier.

This is a philosophical question that I wrestle with daily every night --
0200 in Singapore now.

If someone can share some insights on this deeply philosophical question,
it will be great?

Thank you in advance.

Regards,

Nathan Aw
https://sg.linkedin.com/in/awnathan
https://www.hyperledger.org/community/technical-ambassador
http://www.nasdaq.com/article/guest-post-understanding-the-limits-and-potential-of-blockchain-technology-cm874892
https://www.hyperledger.org/blog/2017/12/05/developer-showcase-series-nathan-aw-ntt-data
https://bitcoinmagazine.com/authors/nathan-aw/
https://twitter.com/Hyperledger/status/938105092644974594
https://www.hyperledger.org/blog/2018/07/24/hyperledger-sawtooth-seth-and-truffle-101
https://www.hyperledger.org/persons/nathan-aw
https://github.com/nathanawmk
https://erc725alliance.org/
https://datatracker.ietf.org/meeting/103/materials/slides-103-dinrg-decentralized-identity-01
https://www.hyperledger.org/news/speakersbureau
https://www.meetup.com/BlockChain-Dapps-Technology/events/254556114/
https://www.meetup.com/Hyperledger-HK/events/248011521/
https://blockchain.ieee.org/newsletter/editorial-board