Ryan, you are correct that in 2008 some of the money went missing, and I believe it happened also in earlier years, before I joined the league. Your proposal is understandable, as it is in the interest of all members of the league, that our money is safe and wisely spent.
However, we also need to consider the efforts to administer. Some teams might welcome the possibility to transfer to a bank account, but others prefer to just collect the cash from the team members and then hand over the money as is.
As we are not a registered organisation, bank accounts could only be opened by individuals, who would then have access and authority to manage the funds. Every time a league official changes, those accounts would need to be changed. Note that only single name accounts are available in Korea.
There is a significant amount of transactions to be taken during the season. Any measures to increase security would increase administrative load of the league officials, which is already quite high.
All of this puts even more significance to elect league officials who are well known in the league, trustworthy and responsible.