"Of course there might be those that would say you are violating copyright by "publishing" a book on your site (even if it were password protected). And there would be truth to their belief since your password could be compromised (either intentially by you or hacked by someone else)."
Well, if "could be compromised" is the test, it could happen to a lot of people. Anything I own "could be compromised" by kidnapping me and torturing me and I admit I would soon give the bad guys anything they want.
I think courts would accept a good-faith effort to try to keep crooks at bay, and would not demand that one set up a situation that could not be compromised, which is of course impossible. Nuclear secrets couldn't be kept, for example.
As to whether this is worth the trouble just to avoid using a USB cable, let me remind anyone following this that you only have to figure out how to do this sort of thing a few times, then writing a script is a relatively easy next step. So we are comparing using a usb cable to sleeping late or whatever.
Besides, doing things the easy way is more fun, no matter how much effort it takes!