How does an account created via Aws Control Tower "Account factory" differs from the account created via the IAM Identity Center?

IAM Identity Center is a service that allows to create users, groups and assign them to multiple AWS accounts or applications. This services helps in centralizing access to your multiple AWS Accounts with the use of SSO, but AWS Identity Center doesn't create AWS Accounts. You must be referring to AWS Organizations.

Back to your question: AWS Control Tower offers a straightforward way to set up and govern an AWS multi-account environment, following prescriptive best practices. AWS Control Tower orchestration extends the capabilities of AWS Organizations, one of them being creating accounts (Account Factory).

The Account Factory is a feature for creating new accounts and bootstrapping them with baselines and guardrails. AWS Organization only creates the account.

References:

• https://docs.aws.amazon.com/organizations/latest/userguide/services-that-can-integrate-CTower.html