I’m not sure why OP specifically mentions the Treo anyway; it is already classified as a smartphone. I know some of the earlier PalmOS devices didn’t have that ability. But I also know some candybar style dumb phones, like the Sony Ericsson, that did also allow installing apps like games and such that existed before the iPhone coined the term. 🤷♂️
I’m not sure why OP specifically mentions the Treo anyway; it is already classified as a smartphone. I know some of the earlier PalmOS devices didn’t have that ability. But I also know some candybar style dumb phones, like the Sony Ericsson, that did also allow installing apps like games and such that existed before the iPhone coined the term. 🤷♂️