How Secure Is Cryptocurrency?
Cryptocurrencies are secured by the blockchain technology as you described it (blocks,mining,timestamp...), except few of them with some dangerous loopholes (Ethereum Classic for instance). However, the danger comes when to secure funds in cryptocurrencies.
In your great article, you have listed the common known risks but it lacks to mention few methods on how to avoid those risks or on how to chose the best method for storage.
Conclusion
You can only select the best way to pick and set up your crypto wallet and other digital assets with seed phrase backups and other wallet setup options and hope to avoid tragic situations from taking place. But keeping yourself posted with information and updates related to cryptocurrency security is usually the best option when it comes to taking the best measures for staying safe in the crypto world.
Despite it requires few security measures to take before/while using, physical wallets are the best tool to secure your crypto funds. I would suggest Ledger Nano which can support many crypto blockchains with the tokens build within (Ethereum with ERC20 tokens for instance).