Actually, it's one or the other. Either it's a hidden tax and, in reality, a bill that deals with housing law, which means the measure's pith and substance fall under provincial jurisdiction. Or it is fundamentally a tax, which means the primary objective is to collect tax revenue, and I highly doubt that. In addition, a whole system has to be put in place in order for the federal government to administer property tax, something it has never done before.
Keep in mind that municipalities, school service centres and provinces don't exactly have an easy time when it comes to funding. For the federal government to encroach on their area of taxation—an area overseen at the local level—is inappropriate policy, especially without negotiation.
The smartest thing to do is accept that there is no magic solution for the housing situation and that each province has its own suite of strategies. For instance, Quebec has rent control measures in place that don't exist in the rest of Canada, and British Columbia uses strategies that differ from those used elsewhere. What the federal government would do, if it were wise, would be to support those strategies, rather than impose regulations that fall outside its jurisdiction.