It requires you to bind your account with a debit card. I am using WeChat for years but I never attach my debit card to it, because I do not have a China debit card. When I need e-money, I just ask my family or give my friends some cash and they transfer e-money to me. That's all. Then I can use the e-money for offline shopping, online shopping, sending Hongbao (as gift-card). I do not understand why debit card is required.
This is mandatory when you ask for an online banking account.
All you do is enter the number on your bank card, they text you a code, you enter the code and the payment or linking of the account is confirmed.
Nowadays most people have already linked their accounts with bank. But you still do not have to. When the feature first released in 2014, most people used the e-money for social purposes like sending gift cards and transferring small amount of cash; people just did not withdraw money.
That's one of the most important reasons why WeChat won tens of millions e-money users in a very short period.
For Alipay, it was already solved when I moved to China in 2010.