Italic -- Styles v Direct

I'm using Word 2000. What's the difference between Italic direct
formatting, and Italic styles? I have set up a character style for
italic. When I insert a document, some of the italicized words update
to match my custom italic style. Others do not -- they show up as
style "normal."

I have took the italic icon off of my toolbar. But I sometimes
use the control+I shortcut. Do I presume correctly that those
keyboard shortcuts apply direct formatting? Do I presume that I may
assign that shortcut to my italic style instead?

I keep hearing that "styles are better than direct formatting."
Ive been working on learning this.

Why does Word even have direct formatting? Does it have any use?

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