My name is Lilith, I'm on the Social Care team at Shopify.
It sounds like you might be referring to the Shopify Payments settings. This is unrelated to your account billing or store being published online. What this would mean is that if you've not set up your bank account in your Shopify Payments settings, we're not able to payout your revenue that can be captured through credit card purchases by your customers until it's set up.
You can head over to Settings > Payment Providers to find the settings for this:
It's very crucial to have this bank account set up before launching your store when using Shopify Payments. If you've not set this up, our system will turn off that payment gateway. This will mean that you'll not be able to accept credit cards as a form of payment from your customers at checkout unless you switch to a different payment gateway or set up your Shopify Payments banking information.
I'd recommend turning this payment gateway off temporarily since you're not able to use it unless you have a valid bank account.
You can in the meantime continue to use PayPal as your main payment gateway to accept orders from your customers that have PayPal accounts.
The sooner you're able to offer your customers the ability to pay with a credit card by activating a credit card processor (payment gateway) like Shopify Payments, the better your revenue will be. You won't want to miss out on a large majority of checkouts by not offering this method of payment.
Once you've got a valid bank account you can activate the credit card processor of your choice. I do still recommend reactivating Shopify Payments since you'll have some significant benefits to using it in combination with any other payment methods on your store.
Some of these benefits include:
Let me know if that helped! I'm happy to answer any questions you think of as you work on your business.