Is there any real advantage to use Position Roles and if so can anyone give me some examples? I've never used it and don't quite understand how to set it up to improve my game.

Position roles are very important (at least for me). You can insert variables that result in a score which then can be used by you (as the coach) to decide which players fit best for a particular formation or position group.

For example:

1. Go to coaching, Position Roles.

2. Select LB.

3. You have options for ILB, OLB, LB1 and LB2.

4. I run a 4-3 defense and in my formations I allocate LB1 as my cover LB. As a result, I allocate attributes that I think are important for a cover LB to rate LB1 players. For example, I place great weight on GI and SPD for a cover LB. Therefore, my weights are adjusted so that my LB's are now rated for my LB1 position.

5. Next, go to Depth Charts. Select LB. Look to the right and you will see scores for the LB1 position (cover LB in my scheme). Now, I can create a depth chart for that particular LB1 position.

6. Finally, go to your defensive formations. Select 4-3 for example. You will have the option to pick a LB to be in cover TE/RB. Guess what? Use LB1 and now you are putting your best player in a position to cover based on the Position Role methodology.

Although this is one example, you can really exert control of your substitutions with the position role option. This has all sorts of good impacts on your team so you can swap out players more efficiently.

Hopefully this makes sense.

James (nitros)

Good answer by Nitros.
First thing you have to learn "Before" you setup Position Roles is Which attributes are important for each position. For example as Nitros said previously, Important Coverage Lb attributes would be Speed and GI. There are others and each position has their own.
Not sure of the link but it is in the GD help files somewhere; a chart that shows important attributes for each position.
To setup Position roles without knowing this is like being a blind umpire.

I've seen quite a few blind umpires.

"When I grow up, if I can't see, I think I'll be a referee!"

(My first paying job was as a referee, and my high school friends were ballbusters.)

My first paying job was as a hitman for the mob.
I would tie my victims to a chair and bore them to death talking about GD. .