However, these projects can be useful: Enigma@home [...] does so cleverly - using a hill climbing algorithm to reduce the number of decryption attempts needed.
Using useful hill climbing algorithm (mixed with brute force method, BTW) doesn't make the project useful. Using brute force method is not a valid argument for de-listing either, if no better method is known.
Further, the Enigma messages have historical significance
I struggle to find usefulness in just being interesting from historical point of view. Also, there are thousands WWII mysteries nobody tries to solve due high cost and no usefulness.
Enigma messages have historical significance, whereas the Moo! Wrapper message does not.
While hidden message itself most likely has no historical significance, some may argue Moo! Wrapper project has historical significance in computer and encryption history.
Does (enigma@home) decoded message you describe here add anything significant to the knowledge already gathered in the books? No.
On the side note - a strong argument for why to de-list Moo! Wrapper I have described here
I don't understand where the issue is. Enigma being "solved" was one of the reasons often cited as a contributing factor to fall of the Nazis. However little significance it has to you personally.
Historical data -if aggregated- could become a valuable contribution to a research project -or a project of different nature- in the future. Knowing more about the past can't be a bad thing in my book.
Does it add anything?
Actually it does: It adds to the exact account of events that happened on that day- in this case a troop/ship movement and the way it's crew communicated their intention of reacting to a new situation.
Maybe I am missing your point.
I agree with this - there is historical value in the messages, which helps build a picture of events during the war.
If you look at it that way, every method is brute force. I consider a brute force decryption to be a full search of the key space, not a guided search that cleverly skips irrelevant parts.
I fully agree with this.
In the article you talked about usefulness and I did not agree with the argument. Being an interesting from historical point of view and useful is two different things.
It's not about personal. I'm arguing above about reasoning.
Can you explain how does it constitute usefulness?
Also I wrote:
Being an interesting from historical point of view and useful is two different things. I don't really stand against enigma, what did I show is that the same reasoning defends Moo!Wrapper too.
Can you explain what useful or at least historically significant is in the message @dutch wrote a very interesting article about? (Linked in my previous comment). While I find decoded message is historically interesting, I don't see why it is historically significant.
Are we still fighting Nazis?
Polish and later British mathematicians did great job. And they had no computers.
The lesson is - usefulness as a criterion for listing and de-listing projects is a very tricky one.