GrabPay Card vs JumpStart Card?

I'm not sure if a similar question has been posed (there's quite a lot about Jumpstart) but I'm looking specifically at these two cards.

My goal is to currently build my savings. I am a fresh grad who just started my first job and is striving to build my savings. For easier context, I do not have more than 5 digits in my savings account.

I've been topping up my Grab Pay Card to make purchases on nearly everything - Bills, Groceries, and certain large purchases above $200. I'm currently holding a UOB One account, but it seems that I may not be able to meet their requirements to take advantage of the full interest rates.

I looked at Jumpstart and was tempted by the lack of fees and minimum balances, plus cashback up to $60 on spending. My question is - with my goal of just building up my finances - do I keep spending on GrabPay Card or should I take advantage of Jumpstart's $60 monthly cashback?

This is because I'm starting to feel the rewards/benefits of the GrabPay Card have become somewhat negligible, and I can easily meet their renewal for Platinum with my spending trend in 6 months.