yes, the need to access the GPIO limits practicality of the serial console some, unless you are willing to perform mods such as http://learn.pimoroni.com/tutorial/hacks/add-a-serial-breakout-to-your-pi (or the abomination I have performed on my Zero).
I am pretty sure I have used Serial to transfer files to a Pi, but admittedly it's not something I do often and may have resorted to a shortcut (copy to /boot and grab from there). Either way, that's a feature advertised so it should be possible. Good point about bluetooth, I shall try and report.
another solution worth mentioning, though limited to the Zero and A+ is USB Gadget. I believe this is coming as part of the next Raspbian revision but it's possible to get going right now (my Zero is hooked up to my AirBook that way as we speak), though it can be painful to set up if you're not an advanced user currently.