An account could be only on one side. The side and chapter is the meaning of this account. Account on the left just negates the increase/decrease direction.
In a bank ledger when a loan appears on a checking account, both increased. Loan on the left, checking on the right. DT Loan → CT Checking. Loan is an asset for a bank, Clients money is a liability.
On a client's balance sheet everything is mirrored. Checking is an asset, Loan is a liability.
Queries are quite simple. Volumes are problematic. In a big institution you would find several ledgers included in the general ledger by totals. You just don't need all the details in one place.