There is nothing that prevents Wikiversity participants from leading and attending "courses" within Wikiversity. Wikiversity participants will do what they think is
Within Wikiversity, the word "course" only has a hierarchical meaning (see WV:policy proposal on structural nomenclature). The Wikimedia board has explicitly guided Wikiversity away from offering courses which include Wikiversity-offered evaluations coupled to earning credit towards a degree.
A possible exception might be when the evaluative component is in fact provided by an accredited educational institution which explicitly makes use of a specific Wikiversity course. Such an arrangement might allow students to use Wikiversity as a medium for providing course content for use by a credit-awarding institution. Note: this is hypothetical; however courses at real institutions do seem to have made use of Wikiversity as a space for sharing some of their work.