Ahhh, though you said "corporate account," I'm betting you actually mean a "Merchant Services" account. There are actually a number of different types of paypal accounts, each with their own set of rules and features. Paypal --very intentionally-- tries to confuse people by not clearly listing both the various types of accounts and the various risks associated with them. They also very intentionally do _EVERYTHING_ they can to get your bank account credentials.

For example, in your situation, there may have been a somewhat hidden link to "other payment options" but of course, the only default you saw was "enter your bank account number." Paypal pulls this shit constantly, and all it takes is one wrong click (or less than careful reading) to trap you into an endless page reloads of "please enter your bank account" nonsense. --It's extremely scammy and they use every anti-pattern in the book, heck, they probably wrote the book.

I should also note, NEVER use a bank account debit card with paypal or online. These are also another way your bank account can be completely drained by attackers or less than honorable businesses.