It is mainly of use when you have a few statements, that you execute often, but where you are unable to hold a reference to the $sth. I've never yet been unable to hold a reference, you can store them in package variables or closures. I'd say its more for when its inconvienient to store the handle, so you lazily decide to let DBI do it for you :)

And I've seen this happen occasionally when people have hashes of column names and values which is when this solution is usually ideal.