Sales Order and Ticket numbers are the most frequently shared indicators when discussing everyday issues in AX. Typically, the first stop in AX is the Sales Order to problem solve. For many of these problems, the customer account number is one of the first fields to verify and/or be used to follow-up on. Having the Customer Account number displayed within a Sales Order's Lines view is handy for any user working in AX (where customer account formats would be a quick visual indicator of selling brand).
It will be great if you can revoke the UI of displaying Customer account number on the sales order line screen in D365.