This is pretty fun and it's great that you're playing and having fun. I try to encourage people to play as much as possible when doing creative endeavors like photography.
It's really up to you in terms of how you use photoshop. A professional photographer will use photoshop to fix color and augment their photographs in subtle ways. Most photographers don't use photoshop to create their works although some people do. For example look at the creative work of Julieanne Kost. Her photoshop and photography are impressive.
Here is an example of her work:http://www.jkost.net/
(of course she works for adobe so keep that in mind)
The point I'm trying to make here is that photoshop and its kin are very very powerful imaging tools.
You can spend a lifetime inside photoshop and go very very deep with it.
At the same time wouldn't you rather be out taking photos?
In this particular image, I agree that it's pretty funny but is it worth it? Would you hang this on your wall?
Take a look at the selection (or the cut out) up close.
One of the most basic photoshop skills is making good selections. It's not as easy as it sounds but that is critical if you want to make stuff lik this work...
Take a look at feathering, masking, and opacity as well if you want to improve on this kind of thing.
See you on the next assignment.