If I'm wrong please correct me, but I think it is because:

 Precedence[Apply]
 Precedence[Compose]
> 620
> 670

What is also an answer to your question about precedences of functions. It is `Precedence`, an undocumented function.

"Good old fashioned" `[]` is safer but I really like `@`, I just have to remeber what is going to happen basing on my experiece, because no one will remember all precedences :)