Counterpart license was something that was used in the past but these green papers are of no use now and instead of that the online system has been introduced. As a lot of the things have been shifted you the online system this counterpart license has done the same too and the reason is that these online systems are more efficient and are fast to operate. These license and counterpart licenses are something that comes as a result of passing the driving license with the help of the driving schools.
Why the online system is now chosen and used is because it is fast and efficient as compared to the other system. This system has been made this way in the United Kingdom while the rest of the world is slowly shifting to the online system. Now you will only have the plastic photo cards and all of the information will be saved online. DVLA will still be operating all such processes still. The benefit of this method is that now the firms that sell you cars will be using their online portals to check your license information instead of reading the whole license paper.