Giving up the Kaesong-Ongjin Peninsula and taking the Sokcho-Goseong line

Is this a net gain at this point? Including military, economic, and tourism aspects?
Also, is the cultural heritage in Kaesong as insane as Gyeongju? Since it was the capital of Goryeo for 500 years, I bet there's a ton of stuff if you start digging lol
The more I dig into the history of the 38th parallel, the more interesting it gets
The photos prove that in terms of land area alone, it's a massive gain of more than double