f# - Why use a Backward Pipe Operator instead of Function Chaining?

Question

Why use a backward pipe operator instead of a function chaining?

let distanceFromOrigin aPoint =
    let square x = x * x
    sqrt (square aPoint.x + square aPoint.y)

vs

let distanceFromOrigin aPoint =
    let square x = x * x
    sqrt <| square aPoint.x + square aPoint.y

Answer 1

Because of the left associativity (f <| g <| x is parsed as (f <| g) <| x and sadly not as f <| (g <| x) which is equivalent to x |> g |> f), I found it useful only when you want to remove parentheses (instead of f (long expression), you write f <| long expression).