Payment accounts are certainly required for any filing with fees assigned to them. Why are payment accounts required even for filings without fees, though?
Each time a user submits a filing, the court requires a payment account to be selected. This is to ensure a valid payment account is captured in the event adjustments to the total of the fees is needed.
Even if there are no fees due for your filing, the site still requires a valid payment account to be added and selected with your filing. This is to ensure the courts are able to process your filing.