It will definitely be possible to automatically export expenses to Concur but perhaps not quite in the way you’ve described…
Once Monzo’s API is ready, Concur or a 3rd party developer should be able to build an integration with Monzo (without Monzo needing to be involved) just like Uber’s Concur integration.
So your expenses & receipts would be pulled into Concur automatically, as soon as they hit your transaction feed or you attach a receipt to them, which would mean that you could completely skip the email step.
To give you some sense of what that looks like, in this developer’s project, his company’s expenses are automatically uploaded into his expense management system. It looks like that would save a lot of time! 
https://community.monzo.com/t/adding-cash-expenses/6994/9?u=alexs