Advantages of attending a conference I am a co-author in a paper. How can attending a conference be beneficial to career and resume since I am not sure whether to attend it.
Unless you are presenting a paper at a conference, there isn't much advantage for your résumé. From a professional and educational perspective, however, conferences can be very informative, for the reasons Peter outlines. 

I would go a little bit further than Peter, however, and recommend that, if possible, you try to attend multiple conferences per year, particularly if you are relatively early on in your career. At least one should be a relatively large meeting, where you can make many contacts in your general field; and one, if possible, should be a smaller meeting or workshop, where you can interact with your peers in your specific field. That way, you get the benefits of learning about the overall field—which is important for networking and job-finding, as well as the close-up exposure to work related to your own.