I have just completed an expert course, by the time one was available I had already done much personal research, particularly with the help of this forum so there were times when I thought I was hearing things at a fairly basic level which I knew already. Common sense has always advised me that, even if you think you know all you need to, it still might be worth listening and you could learn something helpful or gain from sharing views and ideas in a group. Sometimes I disagreed with the advice, the dietary advice is sound but simple, and the time spent on any item very much depends on the mix of the group attending as to how relevant it is to your own situation.
My view would be to go, it is free and you may learn something useful, however I suspect it is much more useful for diabetics who are not doing their own research on forums such as this.