Vacant House Taxes have been tried throughout Canada and are generally ineffective. They are just a distraction.

The main reason why they don't work is fairly obvious: Why would someone own property to keep it vacant?

Sure, there are some people with vacation homes, or second homes where they frequently visit (heck, I might have to get an apartment where my office is located now we're being forced to return to the office). Oh the Urbanity has a great video where they point out the vast majority of "Vacant Homes" are either students who don't permanently live there, in the process of a move, under renovation, etc.