In the beginning it was my understanding that:
- Every address has a private key
- Every address has a balance
- Every address may send and receive coins.
This is simple.
But now I am using more proper wallets (because you shouldn't reuse addresses) and got a little confused about not having one central bitcoin address. In specific - how does an airdrop work if my holdings are split between all these addresses. But more generally, what I read was:
Bitcoin transactions can have many inputs. You shouldn't think in terms of address balances. The protocol doesn't work in balances internally. If you receive 0.3 BTC, then you have a "0.3 BTC coin" in your wallet, not so much an address with a balance of 0.3.
There are many implications. What if I add a private key of an address to two different wallets?
Is a wallet not just a keychain of all these addresses and private keys? I guess not, if so, how would airdrops work, how would you send more coins than one address holds with just one transaction?