PM Carney is being serious.
Campaign Carney is less so, yes, but probably given the crash course in electoral politics he just received, he knows he has an election to win and a mandate to earn before we get down to business. He's got a fine line to walk between these two personas for the next month and IMO he is handling it right so far.
He is completely undercutting the appeal of Poilievre's platform. "He already cut the carbon tax and he's going to lower taxes by 1%? Well I'll cut the carbon tax harder and I'm lowering tax by 2.75%, take that sucker!" But if you asked Canadians how much that additional 1.75% would actually save them I bet you they couldn't give you the number. (The most astute ones would say that the funding cuts to other programs would reduce the net benefit to them).
I make more than the first bracket so I qualify for the full benefit, but I would rather my taxes double if it meant that every person could have a roof over their head and access to adequate food and medical needs.