I'm a little hung up on definitions. A couple of years ago I found a book by accident, searching on the title --- Learning by Teaching, by Donald M. Murray. He was a journalist who wrote for the Boston Globe and college teacher of writing. In the first couple of essays he talks about writing as a discovery process and, apparently, he was one of the pioneers in teaching this approach to writing. The writer learns in composing what is on the page and in editing that content. Writing in this sense creates something new based on the information gathered, the reflection on that, and the synthesis or interweaving of different ideas that occur to the writer in the process of writing.
Do we want to call that inquiry? If we do then I'd argue further that essentially all learning motivated by curiosity is inquiry. Or do we want to narrow the definition of inquiry? It's hard to weigh in on the benefits without having the definition.
In our last session, there was a point raised by the students that it is really different from their courses working on open ended questions, the answers to which produce new knowledge. But that knowledge might be known elsewhere, only not known to those working on the questions.
Since I blog, and I do try to investigate ideas a la Murray, I can comment based on experience about the benefits of doing that sort of thing. I really can't comment intelligently about having undergrads work in a lab. That's outside my realm.