Depends on what you're charging. Game points? The phone bill? Or something like that? The game point card is best to be able to sell a card to you, and some need an account password to let him log in to help you fill, such as Hearthstone Legend.
There is a certain risk, but it doesn't matter if you change your password in time, because you are afraid of unscrupulous people breaking up your card and so on. Phone charges directly Taobao home page recharge, that is still reliable.