I'm a little late to the party but just described something similar at Approaches for linking form instance changes to individuals - #22 by LN.
That seems totally fine to me. In fact, I imagine that Enketo might also want to introduce event types that don't make sense from a Collect perspective.
What we might want to do sooner than later is add a way for the client audit log to include a user agent identifier (ODK XForms client type, client version, operating system, etc).