First of all let's look at what graphic designing is. There are different sites explain it differently. According to Wikipedia
"The term graphic design can refer to a number of artistic and professional disciplines which focus on visual communication and presentation."
What I think that it is difficult to define the term Graphic Design as it cover a number of areas. It is used in making websites, posters, brochures, book covers, billboards, logo, business cards, product designing, branding, marketing, vector art, wallpapers, page layouts, newspapers, magazines, electronic ads, and many many more. Although each of these area in GD need specialization but most graphic designers are capable of doing almost all types of graphic design, but nearly all of them have a preference or specialty they focus on. Each specialist will no doubt have an individual answer to the question of “what is graphic design” as well, but the overall answers will be the same.
Designing is everywhere in different ways. Most of people think that a design should always be decorative but as most of people think design is not always decorative. As a form of self-expression it can convey a specific feeling, emotion, mood, or impression. A design can communicate a message when it incorporates words, symbols, or representational shapes that are readily understood by the viewer. So you see that a design is much more than just combining some photographs, illustrations and text together. It require skills, artistic attitude, a lot of practice and of course experience.
Now the technology is reached to a level where basic qualities, features, usages etc. of most of the products are like same. On the other hand most of the businesses are using same kind of strategies and modes for advertising, promotion and marketing. The competition is very tough and everyone want to gain the maximum profit. Now one thing which make the products different is their look and design. Of course the technology, price and usage does matter but that comes later. The first thing a customer notice is the design of any product. The better look means better chances of sale. That means a design play a major role in sale of any product. This is the direct approach of a design to the customer but except this any business need a design for their website, logo, business card, branding, advertisement, or many other projects also. Graphic designers are very much in demand in businesses. Almost all advertising includes graphic design, as do websites and the other items.
I think any design must start with an understanding of what is required by a given problem, and end with a valid and creative solution to the problem. When I deal with visual forms of communication, my concern includes conveying messages, explaining ideas and thoughts, providing guidance and direction, persuasion, and stimulation of emotions; all of these constitute the functional aspect of design.
Hopefully, this post has given you an idea that why a graphic designing is important. Your comments and suggestions are most invited.