Hope someone can help.

Currently have 40k miles on my BMI card (via the credit card) and 50k on SQ through flights.

About to spend the SQ miles on a flight. Fly SQ about twice a year to SE Asia and or NZ. Never fly BMI.

Just booked a flight (paid for) with SQ to NZ should I use SQ card or BMI? Also should I ditch the SQ card and use BMI for all future mileage?

Your thoughts would be be welcomed.