Certainly enforcement and collection are always challenges, there's no doubt about that. But there are a few different aspects to these cases that are important, even if that isn't a possibility. A deterrent effect is given simply by a country or an official having to go into court to be confronted with the allegations against it. There is even further deterrence if damages can be collected and countries can be hit in the pocketbook.
On looking at the importance of this for the survivors of these abuses, I have worked with many survivors who tell me that even if they somehow didn't win in court, just the ability to get to court and have their story told is a critical victory and step forward in their own rehabilitation. So the chance to get to court, have a story told, and have a fair court in a country like Canada pronounce judgment about what happened is the most important thing.
Beyond that, on the enforcement of the judgment, you can look at any other countries around the world where these countries might have assets. Most counties have assets in places like Canada, the United States, and western Europe, so enforcement would be possible. Even if you were not able to do it in the actual country itself, there should still be other assets and other ways to enforce that judgment and get some compensation for the survivors.