What is the forex markup fee on Indian credit cards?

On the add-on card: yes, the primary cardholder is fully liable for all spends on the add-on. There is no separate credit limit or statement. So only issue it to someone you trust absolutely — spouse, parents. Not friends, not siblings you have money disputes with.

I've been a customer for 6 years. The biggest upside is the customer service. The biggest downside is the slow mobile app. If you do most banking on the app, test the app at a branch before applying — it's surprisingly old.

Yes the rewards sound amazing in marketing, but the redemption catalogue is full of products at inflated MRP. The statement credit redemption is almost always the best value. Skip the merchandise, skip the flight bookings, take the cash.