This is interesting - it is kind of picking a fight with SaaS/cloud providers though, as that is the one kind of software you won't be able to import into your environment: not because it can't do the job, but because you don't have the code. So this would create an incentive to go back to PaaS.

It's definitely true though that a big problem with backend is that you can't easily treat it as a whole system for test purposes.