Yes and no. You have to consider the function of tags in order to determine how to use them to work toward your SEO goals. For the most part, tags serve a two-fold purpose (at least with blogs), and they are: 1) they provide an extra form of navigation for your human visitors, and 2) they promote interlinking which enables spiders to more effectively crawl your site.
Secondary to the aforementioned purposes, and most importantly for this post, tags can also serve as keywords that you're trying to target. Essentially, you can use tags to adjust the keyword saturation of a single post, or of your index/categories pages.
So to answer your question, the amount of tags you use _can_ boost traffic through a well-optimized page, but that doesn't necessarily mean they will.
Hopefully this answers your question, and if I'm incorrect in any of the above information, someone will correct me.
Good luck!
