Source: Secondary reference
Eunjangdo, literally means "silver knife". They are generally thought to have been worn by women as utility knives, for self-defense, or to take their own life when there was no other option.
Eunjangdo were exclusively for higher classes, who had the sole right to wear silver and gold ornaments.
Another interesting function of the silver is that silver tarnishes quickly when it touches arsenic sulfides and as such could be used to detect an attempt to arsenic poisoning. This is possibly the reason they often come with tiny chopsticks that seem too small for actual use.
There is an interesting article on these eunjangdo on Korea Joongang Daily.
A Korean eunjangdo