If you can use even 1 night a year in say a courtyard or similar property each year, go for it. I see a lot of properties with price around 7-10 k INR available under 15k points
Yes, the welcome/renewal benefit is a 1 night voucher upto 15k points. You can top up another 15k points (if you have) to make booking for hotels where 1 nights is upto 30k points for example I had a 1 night voucher upto 40k for reaching titanium (75 nights) last year, I used the voucher and 4k points for an hotel in Dublin which was available for 44k points