If you do not enable account selection, the account selection screen will be skipped as long as the bank does not have an OAuth account selection screen. If the bank has its own OAuth account selection screen, the Plaid account selection screen will also be shown, in order to handle the scenario in which the user makes different selections in the bank-owned OAuth account selection flow than they did the first time through. In Sandbox, all OAuth banks show an account selection screen. In Production, most OAuth banks do, but not all of them. See https://plaid.com/docs/api/link/#link-token-create-request-update-account-selection-enabled