Assalamualaikum,

Dear I am happy to read your post because it was valuable to spend my time on your post as your post help me to know about many new things.

Another characteristic is that it cannot be changed. There is no way to alter or remove a transaction after it has been recorded in the blockchain.

Immutability of Blockchain is a attractive feature of Blockchain as no one can edit or remove our data or information on Blockchain which means it is permanent and a good proof.

The cryptographic method known as zero-knowledge proof (ZKP) allows one party to convince another that they possess certain knowledge without actually disclosing any of that knowledge.

ZKP Is providing us a best way to verify the authenticity of a user in a best way. This application of Blockchain has strong scope and your explanation is also telling it's future.

In disadvantages you mentioned the congestion of network and this is a big problem when the network is congested because it is a bad point for Blockchain if it network stuck and transactions take time to transfer.

Blockchain has advantages as well as disadvantages but as technology lover we should pay attention to Advantages and work on it to help humanity.

Good luck in this contest and hope for good results in this contest.

Regards: @cryptobitcoins