"ocaml_beginners"::[] Having '<<', why to use '|>' ?

Hello !

For f1 and f2 composable functions, writing :

let ( << ) f g x = f (g x)

let g1 = f2 << f1

let ( |> ) x f = f x

let g2 = fun x ->
x
|> f1
|> f2

I usually use '<<' and wonder if we can always supersede '|>' by this operator ?
g1 and g2 are same functions ( not true ? ).
Does it exists a case where the use of '|>' is better ?

Thanks,

Fabrice