TAC is compulsory for specific transactions because it provides an additional layer of security to protect you against unauthorised access to your account.
No, it isn't. Your Internet Banking PIN, which is created at the ATM, allows you to activate the "First time login" at Maybank2u.com. TAC is not used for login but for specific transactions and types of activities. TAC will expire after 2 hours if you do not use it, upon request. Once it is activated, you may still use it for another 2 hours. You may perform several transactions with the same TAC.
For your online banking safety, your TAC can now only be used while you are still logged on to Maybank2u.com. Your TAC will expire immediately each time you logout.