It's the licensing issues. Student version is like what it states, it's price is for students who needs to use the programme for lectures in school or use it to practice at home. No commerical uses or for profit making purposes.
If you are new to photo processing softwares,and need it to only crop or do simple editing/retouching, I suggest you go for simple and cheaper softwares like Gimp/Photoshop elements/Paintshop/Photosuite etc.
I started out since Photoshop version 6 and feels that unless you take a course or have someone really teach you, there's no use if you use the latest version of photoshop because you will not know how to use the functions. You will just stare at the complicated interface and see numerous icons and tabs and will not know how to make full use of the software.