I am not an expert on either QFT or $C^{*}$-algebras but I'm trying to learn the basics on QFT. In all books/papers and other materials that I know, QFT is studied mainly using a lot of functional analysis and distribution theory but I know that some algebraic constructions are also being used and, in this context, $C^{*}$-algebra seems to be the most modern tool. So, what an unexperienced student like me should know about these approaches to QFT and statistical mechanics? What's the role of $C^{*}$-algebras and other algebraic methods in those theories? What are the problems they fit better? If I'd like to study QFT, do I must to learn $C^{*}$-algebra? Are there problems in which algebraic methods doesn't fit well? Are there problems in which either approach is fruitful? What do one lose by not knowing these algebraic constructions?