Reward points might or might not have monetary value, this is extremely hard to prove either way. But it does cost the bank something. When you transfer your Amex points to let's say Marriott; I don't exactly know what happens behind the scenes, but in simple words, Amex essentially buys Marriott points on your behalf at a negotiated rate. This can be 25p, 30p, nobody knows outside of these two companies. Maybe
@BestBanker can help!
Taxing reward points is way more complicated than this though, and I personally don't think that Stree has the capability to figure out such complex structure. The only thing they do is tax these at fixed rate of what the bank is willing to provide its customers. Amex offers 25p for each point when you convert it into cash, so each and every point you earn is valued at that, and gets added to your income. Whatever rate above 25p you redeem this at is your bonus.
But they can never tax these points at redemption level. We're talking about hundreds and thousands of loyalty programs worldwide that might or might not have any presence in India.