One thing I've noticed about our major cities is the presence of cafes, or the lack thereof. Chance is, there will probably be a cafe around the corner or down the block, whether it be a franchise, chain store, or a small-independent cafe. But the presence of these cafes are arguably lacking, relative to Europe and Korea. Many of European cities' infrastructure is designed to be more human-friendly (bike-friendly, better walkability, etc), perhaps allowing better interconnection between cafes and their surroundings. There exists a significant social aspect of the cafe culture as well, highlighting it as a place of leisure and relaxation. In America, I think the mentality is to grab and go - get your caffeine and dip. In fact, a lot of our cafes are kind of designed more around the retail aspect, having an extensive menu and numerous other products like mugs, and less on the cafe-space aspect, offering limited space in relation to the cafes of Korea.
In Korea, you'll find a cafe quite literally around the corner. In fact, you'll find a bunch of them, whether it be 24/7 study cafes, pc cafes, board-game cafe, music-space cafes, pet cafes, or just your normal cafe - some side by side, some on top of others, even some underground. Even amongst these normal cafes, there are clear distinctions, with some being chain stores, and some being extensively (or minimally) decorated for social media. But most importantly, unlike the states, the presence of these cafes are highlighted as they act as focal meeting areas, study spots, date locations, or just a place to socialize. I'm not saying we as Americans don't have this - we do, but I think the idea of cafes as a social/leisure place is more actualized in Korea.
As for why, there are multiple reasons. Korea is a relatively small country with a decent population - major cities lack common areas for people to use for socialization/leisure, and these cafes offer the people a third space. Social media has a very large presence in the younger generations, and these cafes offer decorative spaces for pictures, taking advantage of such incentives. Finally, these cafes are the perfect study spot - food and beverage in the proximity, within the city, and often spacious. As mentioned earlier, there are cafes solely focused towards studying, being open 24/7. I actually was at one of these a few times, and not only is it packed at night, but it is dead-quiet. I think the strong presence of study cafes must have to do with the study/educational culture of Korea.
There has been a term has been popularized in Korea in recent times - "카공족" (cagongjok). It essentially means "cafe study tribe", and as you can guess, it refers to the people who often study at cafes. But the reason why such an innocent act as received a name is because these people will quite literally study or work at the cafe extensively for 6+ hours, almost "living" in these cafes. While long usage of cafes is not inherently wrong, it can often hurt the cafe's profitability as the customer will probably only buy a couple of things, and then take up space. What makes these situations worse is that some people will bring their entire work/study setup, taking up an entire table that could be used by more people. A image below, something I found funny, is a setup a cafe-owner took a picture of, where a customer brought their printer. But all in all, this shows the extreme presence of cafe culture in Korea.