Think end to end from source control, code review, build and CI, versioning to deployment management? This means the SaaS being aware of server passwords in order to deploy the code, all build properties, the code itself etc.
Most of us probably have a hacked together suite of all the above in-house. Would you, or do you already, use a cloud provider for this?
In other words, combine with my build and source control system, but don't force me into a proprietary build system which I have no migration path off of, if you go belly-up.