If you look closed closer to the chart run of Butter, the song started high but lost momentum after few weeks atop the chart. I was in another thread put out said that if Butter can chart for 15 weeks, it will be very successful. However, it is not, take into the consideration that The current Melon chart is still slow and the users number hasn’t been rising back yet.
Dynamite is abnormal, but BTS chart performance in top 10 melon (minus Dynamite) is not good compared with other digital monsters. The gap between Dynamite and other BTS titles/ singles chart performance may lead to confusion about BTS digital, Dynamite doing the number 3 time their second best single.
Why does it have to be 15+ weeks for a song to be considered successful...?
Let's look at the stats of some of the most successful digital monsters of S.K.
IU has 57 entries in the top 10 on Melon, out of those, only 9 songs did 10+ weeks (3 with 15+ weeks, 2 of them released during the 24Hits reform). The biggest hit of her career (TTN) only did 12 weeks (#1 for 2 weeks) in the top 10 but did 120+ weeks in top 100.
BIGBANG has 37 entries, out of those, 8 songs did 10+ weeks (2 with 15+ weeks).
Among third generation idol groups, BTS (13), TWICE (13), and BP (8) are the only groups with 4 songs over 10+ weeks in top 10 on Melon. I do not know how PTD will do, but it could possibly be their 5th song to ever surpass 10 weeks. BTS & TWICE only have 1 song over 15+ weeks while BP has 3 songs over that feat (2 released during the 24Hits reform). It makes sense why BP will have a "better" average than the other two because they rarely comeback and tend to have very long hiatuses, so the public will almost always guarantee them of a hit, similar to 2NE1 & BIGBANG.
I honestly do not know why BTS are always downplayed by girl group stans or soloists for their digitals when they do have similar stats to some of the biggest digital monsters (idols & soloists). However, one of their biggest strengths that most people don't have, except for IU, is their insane longevity outside of the top 10 for their top hits like Spring Day, BWL, DNA, and Dynamite. These are the same songs that appeared on Gallup's top 10 songs for either 2 consecutive years (BWL/DNA) or appeared out of the blue again 2 years after its release (SD, 2019). As well as being stable across all digital platforms and not just on Melon, which is proof that the fandom isn't hard carrying those songs, and have amazing unique listeners (Genie & Melon).
EDIT: I forgot to mention, BTS hasn't done any proper domestic promotions for their releases since early 2020 with ON. So the fact that their songs are doing so well in the top 10 despite of no proper promotions just shows their digital strength. We know how important domestic promotions are for a song to do well, which is why so many girl group stans or soloist stans wish their acts do good promotions and why everyone here on the thread tend to say, "wait until the group/act does promotions (varieties/music shows/big YouTube channels) to see if it will rise or stay stable".