I just find it redundant. You could open the search to guests since the rest of the forums is open to guests anyways. You say this way people dont have to mess with the search engine on the forum, but instead there going to deal with the blog search engine as I doubt there will be access to every article form the index anyways. Plus if people have questions about the tuts this will be more of a headache. First people have to to the blog, search, find, read, then come here, log in, go to the "How to" section and then start a new thread.
Now if we had a tut section on the board, everything is in one central location and you can still allow only certain groups to pose new threads. People can search it as a guest, or register/log in and then go to the tut section, read the tut and reply right there if they have questions.
Thats my thoughts on it. It worked great on the old vbteam so I see no problem with it.