Travel forex cards are available only in certain major currencies like USD, Euros, GBP, AUD etc. You will not get a forex card for Mauritian currency (Mauritian rupees). I have tried using this method for a few countries, but, have realised that I have to get the card in one of the main currencies only. Say, you buy a USD card & use it in Mauritius, you will be affected by currency conversion rates twice (INR to USD and USD to Mauritian rupee). Also, the bank that issues the card has charges per transaction (depends on the bank). If you want to try the card, HDFC seemed to have a hassle-free procedure for getting one. Any Visa / Master / Maestro card will work well.
I never carry cash. Again, you can't purchase Mauritian rupees here. So you might end up with converting currency twice. Not to mention the risks involved in carrying huge amounts of cash. I always buy a little USD or Euros to use while travelling and withdraw money once I reach my destination, using my debit card, in the local currency. I've noticed that banks have a fixed amount as charges for withdrawal so if you withdraw large amounts as & when you need it, this works out quite economical.
Talk to your bank & see what their rules are. But, in this case, you should not forget to inform your bank about the fact that you are travelling outside India (before you leave) and will be using your card. Else, they might suspect misuse of card & block its use. Also, verify if the country you are visiting has the same length of pin that we have (4 digits). Otherwise you may be stranded as you will not be able to use your card.