WordPress comes across more as a CMS (Content Management System), and you might be at loss seeing it as a viable option for E-commerce. We won’t blame you. It is really difficult to justify a free and open-source software as a serious contender for a large-scale and hugely profitable (this is what you must be aiming at) website.
Launched as a blogging platform (WordPress.com), it has come a long way. Now, this publishing platform is powering websites of some of the well-known companies such as Walt Disney, Sony Music, Best Buy etc. But, how viable a platform like WordPress is for a full-blown E-commerce website? If I need to answer this question in one line, I will say, “It is not only a viable but a perfect and fully functional alternative. Period.”