Malaysia is moving from signature to PIN for all credit card purchases as a preventive measure. This is because signature-based cards are easier for fraudsters to take advantage of. It is also part of a worldwide shift to protect credit card users, and many countries such as Australia, Canada and European countries have implemented the PIN-enabled verification. Aside from that, the change was also ordered by Bank Negara to enhance the security of cards.
A PIN-enabled card would reduce the likelihood of unauthorised usage of your credit card compared to a signature-based card because your signature can easily be forged. But to ensure this, make sure you DO NOT share your PIN with anyone else. You should know that it is stated in the terms and condition of cards that PINs are only supposed to be known to the cardholder.