It’s purely for a cheap optics win. President Yoon is a fascist incel that has been taking L after L, so he worked to ban dog meat despite almost nobody eating it except the absolute poorest of society. Dog meat isn’t a delicacy, it wasn’t something people ate because they saw it as high status, it was largely abandoned by an increasingly westernized South Korea, except for those who couldn’t afford anything else. Barely anyone was eating it.
Instead, it’s virtue signaling by a fascist looking to grab cheap publicity wins rather than actually making good systemic change. Dog meat wasn’t an especially pressing concern, it was an almost gone practice out of necessity, coming from food insecurity, especially during and after the Korean War.
TL;DR still a good thing, but ultimately just a publicity stunt to distract from the fascist President Yoon butchering the economy and targeting women, minorities, and disabled people.