1. The prepaid Visa or Mastercard come with an extra fee (like 5-6 dollars per card if I recall correctly?)

2. I didn't see the prepaid cards in stores outside the US, so they are probably not that popular outside.

Sometimes you also want to shift your spending, like if you spend 500 USD this month at this store, you'll get some good % cashback. So you end up buying a gift card that you know you'll definitely use next month.

I think this is irrelevant, TBH.