Every business wants their website to be towards the top of the search listings for the keywords relevant to their business. Being towards the top increases visibility and the chances that a potential customer will visit your website. There are a number of ways in which you can improve your search ranking, but the most effective is to make sure the content on your website is of good-quality and is unique.
Content which is copied from another website will just lower your search ranking as the search engines crawl your site and the site you copied it from will end up with a higher ranking (because someone else is using their content). Why give your competitors an advantage? While it is perfectly fine to look at someone else's website for ideas you should never copy content. You might get ideas on what topics to explore on your site, even rough ideas of layout but these should guide the creation of your own content.
Good quality, original content will not only improve your search ranking but also shows your potential customers that you know your business and know the market. Your website should reflect what your business does, how it does it and why a customer should use your business over someone else's. You want your visitors to come to your site and think "Gee, these guys really know their stuff." Doing so leaves a lasting impression which only helps to cement your business position.
The final advantage of original content is that it avoids legal problems. Material on the Internet is copyrighted and the copying of other's work infringes their copyright in that work. You could potentially end up paying thousands for copying someone else's material in both legal fees and damages. It's just not worth the risk!