Need help understanding pay with rewards

would need to pay 35rs less than the total order value

Yes

Yes , your understanding is fine bro.

Supercoin burning option is not available on all merchants, not on jiomart atleast.

But in most cases the cashback is instant. You will get message from pwr once the cb gets added.

Your understanding is correct.
Additionally, you do not need to restrict yourself to JioMart. You can use that Rs 35 cashback on any merchant that accepts Pay With Rewards. Popular ones include Jio (Fiber and Mobile - Prepaid and Postpaid both), VI Postpaid from VI app, and BookMyShow. Just note that the Rs 35 is valid only after 7 days and for 10 days. Very restrictive but at least they are clear about it.

It's a sh-tty Reward Structure tbh,
- Reward unlocks only after some days (even for recharge payments on MyJio)

- Expiry on reward redemption (like 1 week or so, which is too low)

- No assurance of reward eligibility (have to initiate Transaction to be sure)

- Reward Model: Pay first, Get Reward, Pay again to use that reward (yikes)

- Support Tickets move so slow for a small business

- Used to have an app, but they sneakily removed it from Playstore coz people were mad at their reward exploitation

Occasionally good for JioFiber or JioMart payments, that's all