Are Korean Pokemon cards worth the investment? Nope. Korean Pokemon cards are tempting because of their low prices and high quality cards. But they do not offer the investment opportunity that Japanese and English cards offer.
Korean Pokemon cards sell for drastically less than both Japanese and English Pokemon cards. Generally speaking, it seems that Korean cards will sell for half or even less of what you could get for an English card. And that’s for highly desirable cards. Most cards are worthless, to an even larger extent than English cards.
So unless you rip open a Moonbreon or a Giratina you are not going to get much value out of ripping booster packs. There just isn’t much reason for investing in Korean sets. For example a PSA 10 Giratina V #186 Lost Origin (Lost Abyss Giratina V Special Art 111/100) sells for $1000 compared to less than $300 for the Korean version. So even if you get a highly desirable card you’ll only get 1/3rd as much for it.
And even then you’re going to have a ton of difficulty finding a buyer! There are very few sales publicly listed. So you have the combination of low prices and few buyers. Not ideal! As an investment Korean Pokemon cards look pretty bad.
But, there is a reason to buy Korean Pokemon cards. You can generally get them cheaper than English cards so that means you can enjoy opening more packs for the same price! You can get a Korean booster box of Sword & Shield Star Birth for $22. That box has 30 packs of 5 cards each. So you could buy FIVE boxes of Korean boosters for the price of ONE English booster box.
What’s nice is that while Korean Pokemon cards are generally cheaper the card quality is apparently the same as Japanese cards. And Japanese cards are widely acknowledged to be superior in quality than English print cards. So that’s a nice benefit.
So ultimately Korean Pokemon cards are really only for ripping for fun. There’s very little value in the cards and there probably will never be.