Some prefer paper Bitcoin because most currencies today used as paper currencies and that is the common way but this common way is digitizing rapidly and as an example print out papers that we used in our offices are not used often that much to save money and carbon so instead of that we use an electronic mail system which is very convenient and cost effective than a paper so it is the same for Bitcoin in paper form and digital from so even paper form is preferred today in the future digital from will be accepted as better