The apps you listed (+ other similar apps) are exactly what I use DO for. To me they are the KISS cloud provider. Nothing super fancy but the flip side to that is that they are easy to use and interface with. When I want an MVP or a non-enterprise type app I go to DO. If I want something more complex or something that needs more PaaS-like services (databases, app hosting, etc) I turn to the big three.

EDIT: This is coming from someone who works at MSFT and gets a bit of Azure for free. To me it's all about using the right tool for the job.