It was at RWA conferences that I learned the difference between internal and external conflict. It's where I learned I wasn't a plotter and that there was no faster way to take the joy out of writing than to attempt to be a plotter. I found mentors. Above all, and best of all, I made great friends at conferences. My sharpest critique group is made up of women I met at conferences. The first request I ever had for a partial happened at a local conference. An editor asked for the first three chapters. And when she rejected them, she kindly gave me some insight as to why. The first person to request a full manuscript was an agent I'd met at a conference. (She rejected the book and also gave me some feedback - something she wasn't obligated at all to do and which I appreciated enormously.) So, yes. Cons. 100% worth the time, effort and introvert dread - IF when someone requests pages, you actually SEND them.
However, all that said, I didn't find an agent at a conference. I did that by spamming every agent on the RWA agent list who even intimated he or she might read science fiction. There were nine. One of them read my sample pages, requested the full, read it over Easter weekend, and called me Monday morning. When my first book sold, it sold to an editor I'd never met. (Though later I did get to meet her in person - at a con.) Point being that if you cannot get to a convention, don't stress it. Makes no difference to the people who'll rep and/or buy your book. Do I think I got my work into shape faster because of cons and the workshops? Yes. But if you're taking workshops, trying new things in your writing, getting feedback on your work, and doing your damnedest to incorporate the feedback that makes sense to you? You're in good shape, don't sweat the conference.
Is there a time I'll urge you to pull every stop and get your butt to a conference come hell or high water?