I'm an insider, and I've worked in various online travel companies for a long time, such as e-Dragon, Golden Century, Networked World, etc. I'll tell you why I need a credit card number! In fact, it's not these companies that want your card number, but the hotel that requires it. The main reason is that they are afraid that the guests will NO SHOW, that is, they will not stay if they book it! If you provide the card number, even if you don't go to live, you will be deducted the corresponding room rate! As for whether it is safe or not, it is definitely safe, because the hotel will not cross off your account unless you don't stay! These companies have no right to do so, because banks will not give such companies the authorization to transfer money! To be honest, when I work in these companies, there are quite a few cases where guests don't stay after booking, which will affect the cooperative relationship between the company and the hotel. If they don't go after booking, it will all affect the reputation of the company in the hotel! In the future, when the room reservation is tight, it is difficult to get a room from the hotel. When the time comes, guests can't book a room through these companies, so you need your card number as a guarantee!