The greatest significance of Dynamite is that without it, Eight would have become the most popular song of 2020.
An innocent collaboration Suga did for the effective owner of Edam Entertainment, mainly to give El Capitxn (who used to be called Jang Yijeong of History, now a Big Hit/Hybe producer) something to do, might have swallowed all of BTS' successes up to then.
The Effective Owner of Edam Entertainment, having seized the momentum, would once again dominated the domestic scene, creating another schism between KPop and the general pop of Korea, from which she benefited enormously in 2011 and 2014.
Dynamite ended any chance for the Effective Owner of Edam Entertainment to take over Kpop again, at least for the next 3 years (although I wrote about the possibility that BTS might have reached its peak on the post "Did BTS hit a wall" and if that is the case the Effective Owner of Edam Entertainment might try to strike again).
When they tallied up the Song of the Year for 2020 Eight was NOT credited to Suga, maybe to reduce confusion and embrassment.
If Suga's one line at Eight helped to propel that song to the #1 song of 2020 and robbed BTS's chance to claim the Song of the Year title again, he would have been in a very awkward position as the Effective Owner of Edam Entertainment would boast that at least in Korea itself she can hold her ground against BTS without any pain.
Dynamite ended such possibility and helped to make the Effective Owner of Edam Entertainment realize that BTS is too big for anyone, including her, to overcome so she would come to senses and become part of KPop, something which was so hard for all these years.
That's how I see Dynamite's significance. I see it differently from most people but I have my own way of seeing the world.
