Hi Ben,

were you able to find out the effect of 'Value date' field?

has it any effect on bank reconciliation? anywhere?

The Value Date is mostly used when you want the payment file/electronic Bank file generated from X3 to upload to the bank, to indicate the "value Date" ie. the date the payment is authorized to be processed through the bank account. So if you want to generate the payment file today 01/07/2021 but the Value Date for when the Bank should process it should only be tomorrow then the value date can be used to set it at 01/09/2021. Which authorizes the payments to be processed on the 9th and not the 7th. These dates (and date formulae, execution dates, etc.) are mostly handled within the bank file definitions in Sage X3. 

Therefore it would/should not necessarily make a huge difference accounting wise, unless if your bank file definitions do not have these inbuilt date parameters/instructions.