Ledger settlements enable user to create an overview of due amount on ledger accounts. This functionality is mainly used by accountants to prepare balance sheet specifications. However when accountants are trying to prepair annual reports, they can't request this information historically. AX will only provide an overview of which amount aren't settled. By adding the 'last settlement date' column, accountants are able to account for the balance position at eg. 31-12-2016.
The 'settlement date' value should be populated with the highest transdate value of the ledger transactions selected in the ledger settlement (last date of the ledger transactions with the same settlementId).
This column can be added to the LedgerTrans table and or LedgerTransSettlement table. I guess this depends on the way this functionality gets embedded elsewhere. Visualizing this column might be useful as, one or more older transactions slip in the ledger settlement. It makes it easier to spot errors and also clarifies the progression of the account.
It's a minor adjustment but provides great insight.

Administrator on 2/23/2022 5:42:38 PM
The Settlement date was added with the Advanced ledger settlement functionality, which is now standard (automatically enabled) as of build 10.0.21. In addition, the Unsettled transaction report will now use the Settlement date to determine whether the transactions were settled as of the To date of the report. The trial balance will also be updated to utilize the Settlement date when drilling down to the transaction details and choosing to view only the Unsettled transactions.