Korean chopsticks of medium-length with a small, flat rectangular shape are paired with a spoon made of the same material. The set is called sujeo and is used in traditional eating. They are usually made out of flat rust-proof stainless steel and come really handy for hot pot and daily meal use.
Many chopsticks from Korea are ornately decorated at the grip. In the past, materials for sujeo varied with social class – one could find sets made of gold, silver, cloisonné and so on, but common people used wooden sujeo. Nowadays, sujeo is usually made of stainless steel. Most Koreans use the chopsticks for side dishes and the spoon for rice and soup.
Sujeo (수저) is the Korean word for the set of eating utensils commonly used to eat Korean cuisine. The word is a portmanteau of the words Sutgarak (숟가락, “spoon”) and Jeotgarak (젓가락, “chopsticks”). The Sujeo set includes a pair of oval-shaped or rounded-rectangular metal (often stainless steel) chopsticks and a long-handled shallow spoon of the same material. One may use both at the same time, but this is a recent way to speed eating.
It is not considered good etiquette to hold the spoon and the chopstick together in one hand especially while eating with elders. More often food is eaten with chopsticks alone. Sometimes the spoon apart from chopsticks is referred to as Sujeo.
Chopsticks may be put down on a table, but never put into food standing up, particularly rice, as this is considered to bring bad luck since it resembles food offerings to at a grave to deceased ancestors. The spoon may be laid down on the rice bowl, or soup bowl, if it has not been used. As the food is eaten quickly, and portions are small, little time is spent in putting eating utensils down.
Korean chopsticks are harder to use not because they are ‘flat’ but because they are made of metal, which makes them slightly smaller in radius and more slippery when grabbing something.
Nobody knows for sure what made Koreans adopt metal chopsticks.
If you ask Koreans they will most likely tell you it is cleaner and thus more hygiene (Koreans were obsessed with cleanliness, just look at the old pictures showing farmers walking around in clean white clothes).