RE: Blockchain and cybersecurity: 3 points to consider.
Hi appreciated Sir @pedrobrito2004.
We must trust Blockchain.
These three points you just addressed do not affect the security of blockchains. This type of weakness is typical of centralized systems.
The vulnerability would be if your PC, laptop or mobile device is hacked. There if you would be facing a great threat. But it would not be a product of some weakness of Blockchain.
If for some reason some hacker manages to seize your email or your mobile device, your cryptographic keys would be exposed. This would be a nightmare.