Customers will see the error that their card was declined for insufficient funds. They can choose to try again, or try a different payment method without leaving the checkout process. They will not need to recreate the order if their payment was declined unless they choose to exit the checkout process.
The order was successful in the end. You can see that there is a second payment line that shows the payment was successful, the customer wouldn’t be able to retract that unless they requested a refund.
Valid is a tricky word when it comes to orders. Yes it is an order that has been paid for but always watch out for fraud.
There’s a fraud analysis above the timeline that’s useful. If your store is new there might be some people who try out a few different cards. Looks like this: