Good use of Masking?

programming flash
1

I am quickly learning flash and ran into this question. My understanding of masks may be off a bit.

I am trying to recreate this banner for my learning process.

[COLOR=#800080]http://www.kingairinc.com/flash/traneshow.swf[/COLOR]

Looking at the original flash file, it was used with a series of maskes like this one:

[COLOR=#0000ff]http://www.kingairinc.com/flash/kingshow3.fla[/COLOR]

To me, it looks like I can do the same thing without the masks like this :

[COLOR=#0000ff]http://www.kingairinc.com/flash/kingshow2.fla[/COLOR]

  1. Am I missing something here? Was there a reason for using the masks? I definately have a lot to learn about the usage of masking.

  2. Also looking at the original flash, it appears they imported the jpg, converted to movie clip symbol, then converted again to a graphic? Is there any reason to nest it like that? In both of my kingshow examples at the top, I just imported the jpg, then converted straight to graphic.

Thanks in advance for any insight!

Absorbing knowledge like a sponge!