Most popular Korean music act in history tbh. They were beating even IU on Melon charts before they had to stop and go to military and then Burning Sun happened. Hell IU even had the biggest crush on Taeyang apparently , there are some cute videos of her swooning over him lol.
However, the title of "best boy group" is more subjective and isnt about charts. Their music was very overrated. They had one of the best BG songs of alltime, Bangbangbang, a decent Fantastic Baby, and an older remix/cover song that i cant remember the title of. That's it.
Even Treasure has had more bops than BB tbh.