As if you need a reason!
Here are my top 5 anyway...
5. Free books for door prizes.
4. The classes WILL make you a better writer.
3. You can find critique partners easily in a large group of writers.
2. Agent pitch sessions could catapult you into your writing dreams.
1. You get to talk to other people about your imaginary friends without being judged. In fact, you might even gain admirers. My daughter worded it this way, "You get to be with all the other weirdos."
Have you been to a conference? What was your favorite part? What would you add to the list?