Salt attracts moisture, so when you salt a protein moisture will be drawn to the surface and from the air. Once the salt starts to migrate into the tissue it will draw moisture back into the tissue. There is plenty of moisture in the air to transfer to the tissue and the "amount" of moisture isn't different than what you list above (the exception being if you have too much salt it could draw out much more than desired). Additionally using the right amount of salt and time allows for it to go deep into the tissue enhancing the flavor throughout. What you are doing above is a rapid version. The downside is the salt will not be distributed throughout the tissue, and it could lead to over salting. The open-air side of things is to have the surface be prepped for a nice sear as well as reduce bacteria growth. Hopefully this helps, and if you want to know/experience try it.... :-)