Why would you want to attend a conference that takes you away from your work and costs several hundred or thousand dollars?
That is a very good and important question. You may only have the opportunity to attend either a training course or a conference in a year and a training course looks so much better on your CV, doesn't it? Or does it?
Training, while important to your current employer, addresses an immediate need. Your employer has identified a need for you to have a particular skill set, or you have convinced them during your annual review process, and so it is signed off. "Go and find the training course you need" (before the training budget is slashed).
Conferences probably come from the same budget as your training, so it is fighting for the same opportunity. However conferences are often not going to address an immediate need. They address a long-term desire. Attending a conference will allow you to meet, talk to and listen to other people in similar roles as you, but in different organisations. You will learn about the mistakes they have experienced, the improvements they have made and the ideas that this will spark will enable you to often identify improvements in your current workplace. It will also enable you to network with other people and talk to those people throughout the year. I've never met somebody at a conference who has said that they are happy to talk about things when everyone is back at work, and not meant it. If they are at the conference, they generally enjoy their work and want to grow and help others to grow. So when you get that sticky piece of work and are not sure who to talk to, call upon your network. Someone will have been there before or will be happy to think and talk it through with you.
Conferences are also where vendors are. These are not the terrible people that your mother warned you of, but the people who have products that will probably help you in your job and help keep the cost of your conference down to a level that means you are more likely to be able to get it signed-off. By talking to these people, you will learn about different ways of doing your job, different products to ease the way you do your job or you may even be able to talk to a subject matter expert in the product you currently use to understand what you could do differently, or why you should push to get the latest version in your organisation.
Conference attendance also, in my view, looks better on a CV. It demonstrates maybe not enthusiasm, but enjoyment of your role or skills, and a desire to improve. That is more important in the long-term than a 3 - 5 day course, unless you need to plug an immediate gap.
So get along to the local conference of your choice. There may only be one a year in your country, or there may be several and you have to pick and choose. Many conference organising teams will also be happy to help you justify your attendance if you ask.
I find that the itSMFnz annual conference, and the branch meetings, are a valuable asset for all of the reasons above, so maybe I'll see you at one of those?