The Black Ferns first two games, against Australia and Wales, were not at the level the coaches wanted but they turned that around against the Scots.
Smith said: "I thought we were clinical in that first half. I think we played good heads-up rugby. We were physical, which is important, really physical up front.
"The collisions were great, freed up a lot of good ball and the backs made some great decisions."
The second half had been less impressive as they were restricted to 12 points. But Smith said that often happened when out to such a lead.
He was pleased that 31 of the 32 players in the squad had been given opportunities and those newer players had put themselves in line for future selection.
However, Smith said the Black Ferns hadn't played a complete game yet.
"We've always played a poor first half then a great second half, or great first half, poor second half. I think the focus for us is pretty much to get our game together for the whole 80."
Smith was delighted with halfback Arihiana Marino-Tauhino's display as captain.
Marino-Tauhino said Scotland had troubled them more than the scoreboard suggested.
"Our forwards ran great lines, and we had really good direction from our first-five [Hazel Tubic] and we were picking the right options."
Scotland coach Bryan Easson said they hadn't got up to the pace of the game.
"I thought New Zealand were outstanding that first half and we lost the physicality battle, the contacts were so quick which allowed them so much space to play in.
"It's been three really difficult games for us, but we've learnt a lot of lessons.
"I thought they were picking us off through the middle, they were coming around the edge, they had some attack kicks and we knew that if we could get the ball off them they would struggle with that. We did that well in the second half."
It was up to Scotland to kick on from what they learned during the tournament.
Captain Rachel Malcolm said: "I thought New Zealand were outstanding today. I think they've built across the three weeks.
"Their attack in that first half was probably some of the toughest attack I've ever had to defend against."