What is the point ? You have style 1 and you have style 2 (as well as perhaps other styles) in Illustrator and they are amazing on their own. Well, sometimes it is really great when they are combined and of course this can all be done manually by using a combination of effects etc via the appearance panel and then saving that as the new graphic style but the merge tool, well the merge can just do all that in one go and not only that you may end up with a new truly awesome effect with a totally random effect. I know when I merge styles I am often confident of the end result but sometimes the result can be totally wow and not what I expected
I would always recommend saving your current work before you perforrm the action as the result may crash your Illustrator especially if you merge more than two or three effects and then the wheel of doom will appear and the application will end up not responding. This doesn't always happen though but it is best to be on the safe side.
The Illustrator graphic styles can be merged. To merge, go to the panel and select two or more styles. Go to the menu and select the merge option. Use this option to create stunning new unique effects for your projects. In some cases the effect might need additional work so you will need to manipulate the positions of the fills and effects via the appearance panel
The merge command. Select two or more effects
A gradient added to a rectangle
And merged using the method described - did require an additional change from a normal blending mode to an overlay (some mergings work better than others)
The appearance panel, you can change a blending mode or two to radically change the end merge
1) Open a library via the panel open library command
2) Open a scribble library via the open library command
3) Click an effect in the library (or more than one)
4) Click an effect in the scribble / sketch library (or more than one)
They are now in the main panel
5) Select any of the effects you wish to merge
6) Go to the right side menu and dropdown
7) Select merge command
8) Apply the new style to a selected path
9) Go to the appearance panel - if you wish to further manipulate the effect. The appearance panel is useful as you can move the fills and effects and strokes up and down in the displayed order (as well as the actual appearance of the path).
Moving a fill up or down can radically change the end result. The order of the fills might mean the scribble / sketch or other effect is behind a fill and not seen. With multiple fills and strokes you can end up with many different possible combinations and end results. Also changing settings such as the stroke width of the scribble will also alter the end result.
The initial preset
And another effect (scribble)
And then merged and moving the scribble to the front - - you can see the original gradient mixed into the scribble.
Merge of two line themed effects - one with straight lines up and down and one at 45 degrees. Again, a slight change to blending modes from default to difference was required
Illustrator graphic styles You can find many 100s of great items to merge and create new items with.
A quick video showing how you can create some interesting combinations of styles using transformations such as circular and linear transforms. You can also change the order of the graphic styles to create a totally different effect in seconds from the merge. The example shows a basic line but the same approach can be used with other paths such as type and circles and images and much more.
Merging graphic styles and type (youtube tutorial)
You can create patterns using type and these are added to the swatches panel. The swatches can be modified and converted into a graphic style via the styles panel and these can then be merged in multiple ways in Illustrator. You can select two or more sttles and then use the merge option found on the side of the panel.