Thats not correct. It depends on the power output of this USB port. If it provides 1A output (like older USB ports used to do), then it might be slower than a charger. But if it is a new port and delivers a higher output e.g. 2.1A, it might be as fast as a charger. And if the charger is cheap one that outputs 1A or 1.5A (like many Chinese knock-offs) then the charger might actually be slower than this port!