Gcash Card vs BPI USD Debit Card

Hi! Running into a bit of confusion and hoping for some clarification.

Travelling to Japan for training and we were given USD as per diems. Was wondering what I'd be better off using for small purchases (meals, supermarket).

To my understanding, the Gcash card has no foreign exchange fee, but I'd encounter some losses converting the per diem to PHP.

I do have a BPI USD savings acct with a debit card and can put the funds there. From the site, seems like the transaction fee is 1.5% and there's a forex markup of +/- 1%.

Is my understanding correct that converting to PHP and putting it in my Gcash card will result in the least losses incurred - USD to PHP, then PHP to whatever JPY rate the day of the purchase is vs BPI's 1.5% + 1% (USD to JPY) markup?