Atlas will work with any airline site.
Otherwise smartbuy
Yatra/MMT vouchers from gyftr too, but there are limits on number of vouchers per transaction
No.
However, there is a per-transaction limit of 6000 (regular) points. So for transactions worth 1L and above, you get only 6k points. EDIT - This is only for insurance spends
10k per month for grabdeals.
No limit on Gyftr.
While abroad, if you choose to pay in INR, the currency conversion is done by the card issuing bank and their conversion ratios are much higher than the actual one. If you choose to pay in foreign currency, the card network (visa/MC) takes care of the conversion and that ratio is the actual...