Yes, they do, but AFAICT only in phrases similar to “eligible trade‑in smartphone”.
I think they never used it to refer to their product. It was “iPhone” from the start. Why would they use a generic term to describe a premium product?
https://www.apple.com/newsroom/2023/09/apple-debuts-iphone-1...
"For the first time in a smartphone, color is infused throughout the back glass"
"the Ceramic Shield front cover continues to be tougher than any other smartphone glass"
"iPhone lasts and holds its value longer than any other smartphone"
https://www.apple.com/newsroom/2023/09/apple-unveils-iphone-...
"Continuing Apple’s leadership in smartphone silicon"
"console titles never before seen on a smartphone"
"The best quality video in a smartphone"
"The preferred smartphone for creative pros and filmmakers"
"the first Thread-enabled smartphones"
Lots of results there, especially press releases.