I think the trend is going to point towards these tags being used more. I bet this one becomes a sticky topic like nofollows though. When google first used those, everyone else followed. After years of SEOs debating it finally came out that google wasn’t using them quite like they said they were. IMHO if you can avoid having to use canonical tags by having proper structure, that is the best idea, but if not, using them is better than not.
I’m sure in 6 months we’ll know just how important they are.