I just looked at the website and I would recommend doing this if you are interested in becoming a judge. A course like this is actually not that common, in terms of offering judging education to people who are interested in becoming a judge.
There have been a ton of threads in the last few months about becoming a judge and the lack of information available on how to do it. The first part of this course appears to be about just that, which is awesome. Then you can hear from the leaders in your region how to become a judge, how to go about getting on the assignment list, how many meets you can expect, etc.
Also - if they are focusing on 7/8 there won't be too much to help you with the 5/6 test because a lot of the deductions are different. However, you can take the 7/8 test without having a 5/6 rating. A lot of judges take the 7/8 first then the 5/6 later.
My last words of encouragement to do this are: just because you take the course it doesn't mean you have to become a judge. This will be a good way to see if you enjoy watching routines, finding deductions and doing math

Better to find out for $50 than to find out for the cost of the tests, the NAWGJ membership fee and the USAG membership fee, background check and safety certification...not to mention the uniform.
Good luck and I'll be excited to hear how it goes!!!