Your USB port is not just for USB sticks and isn't pointless.
Solid-state, non-volatile storage (which a USB 'stick' flash drive is) does have its limitations. Each part of the memory can only be written to a limited number of times. Software is supposed to ensure all the available storage is re-used in an orderly fashion to maximise the life of the memory but USB sticks are so cheap now, you have to wonder whether corners are being cut somewhere. How well is the memory management working, for example, and how many times will the media tolerate being re-written?
Zing uses a lot of PC hardware, if his experience is that USB sticks have poor reliability, then that's probably a good reflection of real-world performance.