Directed Acyclic Graph vs Lightning Network Blockchain

Let's have an in depth discussion, put the markets & speculation aside completely. Let's compare these two ledger of numbers for the future of cryptocurrency. With both of these fees and scalability becomes a non issue. So where do they still differ? I don't fully know, so please continue the list and correct me if you will. We should already be able to theorize which one has the best chance to be used as a currency until the end of the internet.
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DAG: Do your own hashing (in iota's case not every hardware can do this, but can this become a non issue with other DAG's like hashgraph?)
Blockchain: Miners do your hashing (+)
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DAG: No mining centralization (+)
Blockchain: Mining Centralization
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DAG: Split internet/firewall doesn't split the currency (+)
Blockchain: Split internet/firewall will split/hard forks the currency forever
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Questions: Bitcoin can be forked/updated in a decentralized (mining-centralized) manner. How can a Directed Acyclic Graph be updated? Only when a new coin does a 1:1 airdrop and the free market begins to adopt new coin?