Graphic Resources

There are a few.

Vector graphics are more "scalable" than raster graphics. By this, I mean you can draw a design that's six inches high, enlarge it to four feet high, and still have it look sharp. If you did that with a Photoshop file, the picture would become extremely jagged.

Vector graphics' filesizes are smaller than raster graphics' filesizes. If I were to build a 12-inch square item at 60dpi, which is my standard resolution (you can get away with that if you're printing things that are to be viewed at a distance), and I did it in Photoshop, the file would be about 2MB. In Illustrator, it would be less than half that. I have a customer who gets pickups wrapped; I can do a whole pickup truck side in Illustrator in less than 20MB. That won't happen in Photoshop.

Vector graphics tend to print faster than raster graphics do, and the prints are cleaner looking.