The article seems to be rather incomplete. Just off the top of my head I notice the absence of anything regarding foreign affairs at all, let alone tariffs, and no mention of sales tax, national defense, food safety and supply management…
Presumably, it's pruned to focus on the things people confuse. But these days that's likely to include foreign affairs and trade. I don't think premiers are normally anywhere near as involved in that as currently, and I don't have a solid understanding of provincial authority there myself.