if you’re copying single layer to single layer or dual layer or dual layer and are not removing any titlesets or audio tracks and do not require any transcoding then you can use the “copy eixsting files” option and select the original dvd where it asks for the input folder and select the dvd writer with the blank in it as the output.
this is, however, not recommended because if you run into any glitches (reader has trouble reading the original, drive slows down so it can better read the data) then the data flow will be interrupted and you have a coaster on your hands.
yes, it’s possible. many people burn this way, but overall it’s pretty much at your own risk.