The first reason is that this is what the register was being prepared for, to support a program such as this. Obviously, at some level, policy-makers wanted to do that.
Second, there's no doubt there may be a greater benefit from commercial properties in terms of what gets returned to the fiscal framework. However, if you look across the full range of our country geographically, small towns, and so on, and where challenges may be greatest, the very tiny amounts that might be spent on restoring Sir John A. Macdonald's summer home in Rivière-du-Loup might be.... Well, that's not a good example, because it operates commercially for some of the year. However, for a small place such as that, it might be a tiny, modest amount, but it can have the greatest positive impact in assuring the preservation of that heritage.
Overall, we shouldn't distinguish between commercial and residential and other uses; otherwise, we're going to be driving people to take a place that might be in residential use and put it into commercial use, where that might not be the best way of ensuring the ongoing preservation of its heritage character.