Hello,
Some countries don't support paypal so for the users who want to buy Spirit Stones, they can't buy it even if they want to. So I think there should be another alternative payment methods like credit card payments.
Alternative Payment Method
From what I have seen, you can use google pay.. But I don't know for certain.
How?
I'll add this to the faq...
Oh, I think I got it. I wasn't using the app. But now I install it and I can indeed buy using it. Thanks for the help.