Exactly. That is the economic perspective. For the entertainment companies it is just another market. For SA a way to show everybody what a great reformer Prince Mohammad bin Salman is (which he is not).
If the korean entertainment companies think this is going to be a permanent market, they are going to be disappointed in my opinion. SA is still under Sharia law and religious figures have a lot of influence. Music is still haram. There is a really vibrant underground music scene in SA, and you can still buy music (because people love music and capitalism doesn't care for religious laws), but it is watched and criticised by religious figures. Schools still teach that music is sinful. Kpop goes against everything that these religious leaders teach: dancing, feminine guys, sexual concepts that involve gay fanservice... So I think establishing Kpop permanently is going to take some time, in my opinion. And time is something that Kpop never has since their entire music industry seems to be build on the concept of keeping groups for a really limited time.
I don't think I would compare the American music industry with Kpop in terms of political engagement to be honest. I am not American, so I am not entirely sure, but I don't think that the US ever used music to blatantly change its image abroad. It not only increases their soft power, it is one of their main tools of soft power. They have been doing that in Asia for years now (which is why China limited Kpop) and only just started to expand this strategy to the west, and now apparently the Middle-East as well. It is really interesting, because they are artificially creating interest in their entertainment to influence public opinion on Korea and then influence politics through that.
I think Riyyadh is politically significant because they are the first Kpop group to perform in the capital city. Other groups only performed in Jeddah (which is less conservative I think), so they were less "important", if that makes sense? Besides, political figures would probably not want to travel for a concert. And being photographed with a foreign music group, ones that are UN ambassadors no less will make the Saudis look good internationally, so they probably won't want to miss that opportunity.
Is anyone still believing in this whole authentic crap? I have never seen anything remotely organic in Kpop. It is the most capitalistic form of music, based on exploitation of young people to line the pockets of a few people and help uplift Korea's image abroad. If I think about it, Kpop/ BT$ and SA are actually a good fit. They will probably learn from each other.