point conversion i find to be risky because vistara cancels flights on the routes that i take (sometimes between 2 metro cities). you dont want to get trapped once you convert your points.
and there are limited seats in a flight that can be booked via points. so it may happen that you have cv points but can't redeem.
so i usually book on smartbuy only, pay 30% using dcb and also get 15% rewards on that 30%.