Layer styles are useful when they are used correctly, but I'd stay away from the bevel / emboss effect for the most part until you have more experience with it.
I only really use the bevel / emboss effect when adding gloss or a slight sheen to my layer.
Example:
The only thing that differentiates the first block of text from the second is the addition of a layer style.
From my experience, layer styles are mostly useful for adding effects to text. For more advanced graphics, particularly emblems or graphic logos, you would probably want to become familiar with Illustrator or another vector-based software package.