Here (University of Canterbury) we use CodeRunner as an assessment tool. Students develop their code in an IDE (we use Wing101 for Python and various other IDEs for other languages) and are expected to test it themselves before copying their code into CodeRunner to have it graded. We think of development and assessment as separate activities, so it's not meaningful to talk about profiling and debugging within the CodeRunner context. This applies even in exams: our on-line examination environment still supplies students with all their normal development tools, but with restrictions such as disallowing of Internet access.
Your question suggests that you want CodeRunner to serve both roles: development and assessment. This is both controversial and problematic. It's controversial because most lecturers want students to learn to develop programs in a "normal" way. They want students to become familiar with the tools of the trade and to be able to develop genuinely useful programs that can be run outside a browser environment. It's problematic because of the lack of interactivity (a CodeRunner submission is inherently a batch execution) and the sheer complexity of providing anything approaching a full set of development tools within a browser. The Python visualiser is a great tool for visualising simple programs - we use it a lot in lectures - but it handles only a limited range of Python functionality (e.g. no file processing or GUI application support) and isn't appropriate for more-complex applications.
That said, I believe some institutions do use CodeRunner in a stand-alone mode and certainly students sometimes try their luck by typing code straight into CodeRunner rather than testing it first. To what extent should we encourage that?
The soon-to-be-released precheck capability of CodeRunner allows question authors to provide students with a penalty-free run against a limited test set specified by the author. Use of this will probably further encourage students to bypass the IDE development. For that reason, some lecturers here have expressed strong doubts about the wisdom of using the prechecking capability. It will be interesting to see how much uptake there is.