Of course it wouldn't deliver justice itself, because it would be simply a commission of inquiry. It wouldn't have prosecutorial powers, and it wouldn't be a court. I don't want to pretend that it's the magic formula that is going to solve all Burundian problems, absolutely not. But to me, impunity lies at the heart of this crisis, and you see it in the way the perpetrators behave. From the low level, the ones who actually do the killing and torturing, right up to the top, there is this feeling that they know they're going to get away with it, and at some point, that has to stop.
The commission of inquiry would do two things. In a way, it's perhaps a bridge between the monitoring and reporting, which there has already been quite lot of, and ultimately some form of justice. The way I see it is that the commission of inquiry, if it's set up, would go deeper and further than, for example, the investigation team that has just submitted its report, and it would be able to gather evidence that could form the basis of, or contribute to, prosecutions.
Then the question is prosecutions by whom? The International Criminal Court is one option. There could conceivably be courts in other countries under the principle of universal jurisdiction, maybe.
At the moment, the Burundian justice system unfortunately is totally lacking in independence and has proved itself unable to deliver credible justice, but maybe that can change in the future.
I don't know if I've answered your question properly, but that's how I see it and what I see as its usefulness.