Because it's highly dependent on scope? Like, if I wanted to template each list item in an array, I could use array_map with another template function, but here

Because it's highly dependent on scope? Like, if I wanted to template each list item in an array, I could use array_map with another template function, but here I would have to keep re-assigning a variable in a foreach. And it seems to be unclear on how you'd pass array and object members to it? It seems very much to encourage variable creep?