You have done a great job explaining Blockchain and talking at length about the genesis block. No doubt, the block is an important feature in Blockchain as it contains the data of our transactions and stores it securely, and blocks of different transactions make up the blockchain.

Also it would be nice if there can be an improvement on the reversibility function you mentioned above. I think networks have worked on that a bit, example is when you are about to send to an address off-network, it notifies you that it's not correct but I believe there can be more improvement. Well done and good luck.