the 7zip rabbit hole goes extremely deep. (1000's of crashes) (youtube.com)
Koreans still pay utilities on top of this.
Because a long time ago, banks didn't offer good interest rates, so people found other ways. Jeonse is like you pay, for example, $50k USD equivalent to the landlord for 2 years rent. At the end of 2 years, you get $50k back, as long as he didn't go bankrupt. During that time, he uses the money to make investments or whatever. Years ago 70% of people in Seoul did it but now, due partially to increased scams and non-repayments, only 40% chose to do this rather than select a regular-rent apartment.