Nowadays credit card offers interest free instalment for large purchase (eg. Facial packages etc.). Is it better to pay the entire amount or go for the interest free instalment?

You should pay the entire amount. This is because credit cards almost all have annual fees. Some banks are willing to waive them for you if you call them and you use their card frequently. But if you are in an instalment, you will have no choice but to pay for the annual fees because if you were to choose to pay the leftover amount halfway through the instalment, you have to pay extra. Banks will have the advantage on you when you are on instalment.