There is actually a few South Koreans playing pro rugby in Japan, they brought a few of these guys into the fold for the first time in a while to play this tournament specifically. One of the Japanese props at the WC is actually South Korean as well, he’d be comfortably their greatest export at the moment.
The biggest thing for them would be the money they will now get from the government to support the sport in the lead up to the Olympics. Interesting that they already have a modern rugby specific stadium that holds 5000 people, which is more than most unions have at their disposal.