It’s the least painful, most economically efficient way to encourage those things and other transitions. When it comes to transportation, higher gas prices have historically resulted in a market for more fuel efficiency (and inflation-adjusted low gas prices have lead to oversizing of vehicles). Unlike the 70s, this time, the carbon tax is brought in slowly and smoothly over many years to encourage conservation (including the things you mention), drive demand for more fuel efficiency, and in the long term, encourage the electrification of the remaining fleet.
The vast majority of Canadians want the government to do something serious about climate change, but they don’t know what that thing is. Economists said a carbon tax and rebate was the most efficient, but public support isn’t driven by economic papers, but by propaganda machines. It’s just too easy to blame the carbon tax for everyone’s problems. It’s the perfect boogeyman for inflation. Heavy handed regulation of industrial emitters would probably be the most supported by the public, but it would have a terrible impact on Canadian industry, and actually be limited in it’s effectiveness, as most of Canada’s emissions would still be “free.”