Hi fgo us players, how u guys choose region for this game as only Singapore is the nearest region for this game?

Currently, i choose Singapore region (working in Sg) and buy Sg google gift card to get the quartz but i know that the cost of buying quartz using debit/credit card directly with selecting US region is the most cost efficient to buy quartz. So, can i make the change to us region and use debit card without any consequences? (like kena ban)

Thanks for the answer, may i know how guys buy quartz? Through seagm?

I see, thanks.