Someone requested this feature in the past, but is the feature available now? This feature is available in lots of other forms, so it can’t be that hard to implement … 
I’d like to have a form saved regardless of payment status. That way, if the payment piece has a glitch, we have a record of the submitted form. In this scenario, I can give them a simpler form to use for submitting payment, instead of having people re-submit a lengthy form.