Question: Can my Bitcoins vanish/disappear suddenly? If it's virtual and immaterial how can it be secured?
No, Bitcoins won’t disappear suddenly unless:
- Your Bitcoin ID is stolen and sent to another address by someone else.
- The market itself faces a problem of its existence somehow.
As long as you keep the encrypted key by yourself, you will always have the full access and authorization to manage your funds.
Technically speaking, Bitcoins cannot vanish just because they are virtual as the balances are stored in a large distributed network and it can only work correctly with a complete consensus among all users.
Bitcoin users can also protect their money with backup and encryption.