Function
Submitting sends an approval link to the address the account holds today — not to the requested one — and the confirmation names that address, so a learner who mistyped is not told to check an inbox they cannot open. Only when that link is followed does Better Auth ask the new address to confirm, and only the second link moves the account.
An address that already belongs to another account is answered exactly like a free one, which is what keeps the form from telling anyone who is registered. The address the account already holds is refused here, before anything is sent.
Render it only for an account that has a password; AccountSection decides that.
The Profile page's email form: moves the account to a different address, behind two links.