PayPal's checkout site will usually offer the option to pay with a credit card, instead of requiring the buyer to use a PayPal account, but it's up to PayPal's discretion; this help page explains the criteria we're aware of that they may use to determine that:
The message in your screenshot is the generic thank-you page message we display when the buyer arrives at the thank-you page before the payment processor has confirmed completion of payment to our system. E.g., sometimes it can take PayPal longer to complete processing a payment than it takes the buyer to finish checkout; apparently this may be more likely if the buyer just registered a brand-new PayPal account to make their payment. Payments funded by eCheck are handled by the banks just like a real, paper check, so those can take several days to clear.
This is why we normally send the buyer a thank-you email once we get confirmation of completed payment, including a link to reach their order's thank-you/download page in case they did not or could not proceed there immediately following checkout. If you are selling downloads, the buyer has to visit their thank-you page at some point to claim their download, which would trigger the conversion tracking pixel you placed there even if they didn't/couldn't visit the page immediately following checkout.