There has been some discussion in comments lately about what the point of conferences is. Some people have suggested that the point is just to get a line on the CV. But while I like getting lines on my CV, I don't see that as the point.
For one thing, I don't see it as just a line on the CV. I hope that my conference activity demonstrates to search committees that I am an active participant in the profession. I hope it shows that I am out there presenting papers and doing stuff. (In addition to getting stuff into journals.) I hope that they don't just think I wanted to go on a junket to Omaha.
For another thing, I typically find conferences to be extremely helpful. Although I've been to some clunkers, I've also gotten excellent feedback from commentators and during Q & A sessions.
For another thing, I enjoy commenting on the work of others. There are gaps in my philosophical education, and commenting helps me to fill those gaps by forcing me to write a short paper about something I usually don't know an awful lot about going in. (Now, I don't comment on stuff I literally know nothing about, but I've learned a lot by commenting on papers in areas related to those I work in, but haven't thought deeply about.)
For another thing, conferences provide a nice opportunity to catch up with old friends. One of the drawbacks to the academic lifestyle is that you usually don't end up living very near your friends from college and grad school, and the right conference can make otherwise impossible reunions happen.
So I guess I think conferences are pretty valuable.