I think, but am open to correction, that bank transfers can be used when paying IRM directly, but not when paying the company that operate partial.ly.
From their FAQ:
Can I use a bank account?
US customers with a payment plan with a US merchant can add a US bank account by selecting the tab and locating your bank on the list. Once you select your bank, you will be redirected to log into your online bank account.
My bank is not on the list.
Unfortunately, you will not be able to use your US bank account if it is not on the list. Please use a debit or credit card.