Delete, Create Check Function (AX2012)

Go to Cash and bank management/Common/Checks,
on “Checks” window, what’s the “Delete checks” and “Create checks” buttons for?

I don’t know whether my answer is relevant for your question. using those buttons you can either create/delete the checks.

Ex: you got a check book from bank, so you need to update the check numbers in the system right. You would do that by using create checks function.

If in case, you lost two check leafs, you can delete those check numbers using “delete” button.

What’s the whole purpose of creating/deleting checks on this window rather than issuing/voiding by AP payment journals?

To issue a check through payment journal, you would need to create the checks first. Unless you create them, you can’t issue them through payment journal.