Dynamic dispatch is in the language too.

    use core::fmt::Display;
    
    fn show_monomorphic<T: Display>(first: T, second: T) {
        println!("{} then {}", first, second);
    }
    
    fn show_polymorphic(first: &dyn Display, second: &dyn Display) {
        println!("{} then {}", first, second);
    }
    
    pub fn main() {
        show_monomorphic(17, 23);
        show_monomorphic("fnord", "slack");
    
        show_polymorphic(&42, &"quirkafleeg"); // mixed types!
    }

There are things you can do with each that you can't do with the other, but they are often both viable choices.