High ranking metrics will result in getting your site on the top position of several charts such as Top Alexa sites, Top WOT sites and so more. People usually go through these lists to discover new sites and hence you will be getting referral traffic as well. Who knows? Some of those traffic may be your next big client or loyal reader of your blog.
Not all web traffic is welcomed. Some companies offer advertising schemes that, in return for increased web traffic (visitors), pay for screen space on the site. There is also "fake traffic", which is bot traffic generated by a third party. This type of traffic can damage a website's reputation, its visibility on Google, and overall domain authority.