Yes, GPU crypto mining is still profitable. It just depends on which coins you mine.
To use Bitcoin, user generally needs two things: Private Key and Bitcoin Address.
Earlier Bitcoin Wallet used to be a bunch of private keys. In order to use new address, user had to generate new private key which made...
When you send Bitcoin from your wallet to some other address it needs some time for transaction confirmation in the blockchain.
Paper wallets if done right are one of the most secure ways of storing bitcoin especially if done on an air gapped computer.