In your game, when you're far enough, there's a feature called "QR Scanner".
Use that to scan the code. (It's the same as Magearna in Sun and Moon, also scannable for USUM)
Yup, the Japanese game discs.
When scanning them on a JP 3DS, the respective Pokemon will become "seen" in your Pokedex,
and you get 20 Points instead of the usual 10 Points, for scanning a QR code. (referring to points used in the daily Island Scan feature)
The collection is more for novelty sake since,
if they are not in Alolan Dex, you can't tell that you registered them,
but if you don't own them, it'll save time on the GTS. (search by alphabet, rather than typing out the entire name)
Also, we don't know if they intend to add the National Dex to USUM.
(If they do, it may come in useful)
Thanks! I saw your Ditto Pika in the Event Gallery and was inspired by it xD
I have checked this album they should all be fine now.
I'm going to check the other album in a few days.