If you are coming from india definitely usd , do not bring rupee, thenexchange rate is so low for rupee
Yes you can exchange INR but the rate is very poor. For other major currencies the exchange rate is generally close to the XE.com rate. INR way off.
Do carry money in USD - you get good rates on USD exchange in both India and Bali.
We carried ~500 USD for 9 day trip. Fell short of money and used ATM with my HDFC bank master card.
Difference between using card and cash is < 5%. Wherever possible use card - restaurants, entry fees, etc.