It is easy (and important) to get sucked into the minutia and detail of what you are working on technically day-to-day. However, this makes it hard to get a broader perspective on what new technologies and advances you could be taking advantage of. Conferences are a great opportunity to break from the rigor of the daily-grind and explore new frameworks, dev practices, and technologies that may be what you are working with tomorrow.
Also, my favorite part of conferences is the hallway track — you can find a lot of interesting folks to talk to between and even during sessions. If there is a slot with no sessions you are particularly interested in, you can often learn more by roaming the hallways and starting up conversations with other attendees and speakers. JAXConf is a great place to do this in, because it has a high concentration of folks in the know — great ratio of speakers, and very technically astute attendees based on my past experience.