"You can really feel the team gelling. There's an incredible vibe within the team; there's a vibe within women's rugby. There's huge joy in getting these opportunities and there's a lot of gratitude in the women's game."
It hasn't just been their work on the pitch that has caught Smith's attention, but off it as well.
"We went to a school yesterday - we thought maybe two or three would come along, but there were just about more Black Ferns than kids there. It's outstanding," Smith said.
"Their attitude is outstanding, the love for the game is brilliant and there's going to be real competition. I love this team; I love the girls – it's hard not to. But that makes it more difficult from a coaching and selector's point of view. It's difficult enough picking teams, but when you're creating something you're proud of, it's difficult to dismantle that and put others in, but that's our job.
"We have to pick the best team for the Rugby World Cup and there are still a lot of hoops to jump through to get there. Those dates are coming up pretty quickly, so there's a bit of pressure on the selectors."
With just Saturday's match against the United States and an August test against Australia on the schedule before October's World Cup, there will be limited opportunities for players to put their hands up for inclusion in the squad for the major tournament.
With two players making their debuts, Smith said it would be up to their teammates to ensure those debuts were memorable ones.
"For Nat and Lucy, it will rely on the rest of the team how good their debut is, they can't go out and really shine unless the others go out and shine. I'm hoping the team understands that and really stands up for them. I'm pretty sure they will," said Smith.
Among other changes to the team that shutout Canada last weekend, halfback Arihiana Marino-Tauhinu and hooker Perese will make their first test starts, as does midfielder Sylvia Brunt.
Black Ferns team to play USA
Whangārei, Saturday 4pm
Black Ferns: Renee Holmes, Renee Wickliffe, Amy Du Plessis, Sylvia Brunt, Ayesha Leti-I'iga, Ruahei Demant, Arihiana Marino-Tauhinu, Liana Mikaele-Tu'u, Kendra Reynolds, Alana Bremner, Chelsea Bremner, Joanah Ngan Woo, Leilani Perese, Natalie Delamare, Phillipa Love.
Reserves: Georgia Ponsonby, Krystal Murray, Lucy Anderson, Maiakawanakaulani Roos, Tafito Lafaele, Kendra Cocksedge, Chelsea Semple, Hazel Tubic.