The only limitation when using USB is connection speed (USB3 is fast enough) and mass storage speed. It's really important when you have a large amount of storage to transfer. It can also be connected to a tablet, helping to improve the user interface when you want to take a lot of files with you. Tablet operating systems are ridiculously slow and inefficient. At least it helps some. (I'll only deal with removable PCs in the future and the tablet OS is really bad - like running multiple apps and even deleting a file from my PC when connected causing it to crash - and this is a high-end tablet from Samsung! )
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