Part I: WTF is Account Abstraction

Because your private key is your account, losing your key means losing your account.

a very important design choice of the Ethereum blockchain: the concept of Account (the object holding your tokens) and the concept of Signer (the object authorized to move these tokens) are basically the same thing!

In summary, account abstraction moves crypto from the current approach of one-account-fits-all, where someone can lose everything with a small mistake, to a future where an account can be tailored to someone's needs. Where you can build a safety net for self-custody. And give them much slicker UX too.