lazy vs fun

[Warren Harris <warren@metaweb.com>]

Is there any advantage to using lazy evaluation in ocaml rather than  
just using thunks to defer evaluation? E.g.

let x = lazy (3+4)
let y = Lazy.force x

vs:

let x = fun () -> 3+4
let y = x ()

Perhaps it's just that the type int lazy_t is more informative than  
unit -> int?

Warren