Do you use Box<[T]> often?

I got to the smart pointers section of the book, and at first I thought that it would make a lot of sense to change my Vec<T> for Box<[T]> in a lot of places through my code.

A lot of times I know that my number of elements is not going to change, but once I started to try it out, I am finding it not as ergonomic (?).

I think that most of my problems come from the fact that Box<[T]> doesn't implement IntoIterator. Also, most times I am just populating a Vec and then calling into_boxed_slice, but at that point I already have a Vec, hence I think I am probably not doing it correctly.

Do people have suggestions on things I should look at, or examples where Box<[T]> shines? Probably I am using the wrong function signatures, so I struggle unnecessarily using/passing around my Box<[T]> (?).