This is a general, wide ranging question which is really asking which is better; paper or digital, because drawing gestures using different methods is the same as drawing anything using different methods. It will boil down to which one you personally find easier, it will be different for everyone. I suggest you try both to see which one you like the most. Who knows, you may find them to be equal. Personally I find it easier to use paper, it's also a bit more convenient and cheaper when going out to say, a park. As all you need is a pencil and a sketch book and there's no risk of batteries running out. I'm just an amateur though so please do take other peoples advice too.