Please help me to understand some fundamentals

Question

A little help will go a long way, so I appreciate any guidance from the community...

If I set my application as the parent of another application, then does that give me any advantage such as subscribing to the child application's message events to effect change or manipulate the child forms?

For instance, if I set my form as a parent, can I hide one of the child forms before it actually gets drawn to the screen?

I am just trying to understand the benefits of setting as a parent other than the obvious being able to run the child app within a custom window.

Is there any other way to prevent another application's window from appearing before it actually becomes visible?