Chapter 3 got rid of some weapons, mechanics, and vehicles, but reminded of old techniques, including double shotguns.
Chapter 3 season 1 is dictated by rifles, they are fast-firing and really deadly. Shotguns have a hard time competing with them, which is why players quickly found themselves trying to find new solutions. It turned out that the double shotguns had made a comeback to some extent.
They are not incredibly strong, but they do give you an advantage over people who fire without switching weapons. Sometimes, especially in 1v1 duels, it can make a big difference.
How big is the difference?
This is not something that will matter in every duel, but you can actually lose a few seconds. That is why many people try to counter all the SMGs with double shotguns.
Of course, this requires appropriate tactics, you cannot shoot the enemy from a distance, rather try to get as close as possible, which is associated with the risk of fighting against SMG. You definitely need to aim and build well to try to cover behind the wall after the shot.