It's easy to gain users, when you give away money. When you used PayPay during the original campaign period they discounted purchases by 20%. At random, they w

It's easy to gain users, when you give away money. When you used PayPay during the original campaign period they discounted purchases by 20%. At random, they would also pay the whole price, without deducting your balance. I've been told they had a 100MUSD budget for that campaign. Essentially they threw money at user acquisition. By using PayPay you were getting free money... it was kind of nuts not to use it. So, it's not surprising that they gained so many users. On top of that, digital payment systems were already popular in Japan (as well as being able to use your railcard for payment, there's a bunch of store cards/other digital payment cards).