I believe you mean the first few lines of Part 3, Section A, article V:
The Contracting Powers may retain respectively capital ships that
were in existence, or under construction and not suspended, on
November 1st 1920, such that the numbers and tonnage of completed
capital ships in possession of each Contracting Power at any time
shall not exceed the numbers and tonnage allowed each Contracting
Power, as prescribed in Part 3, Chapter A, Article IV above.
So any BBs laid down after November 1, 1920 cannot be retained, but you can still lay down BBS between November 1, 1920 and December 31 1920. (However, you might get a conflict with your infrastructure points this way (... or was it factories ?) if this ship is not included in the calculation)
A Nation with aggressive tendencies might do something like that to make it clear to other nations: 'Look ! We have the ability to build something on this scale. We shall abide to the treaty but beware... If anyone dares to violate the treaty, we shall build ships of this size.'
For all we know, if you sim this ship, you might get a design failure or an instable ship or a poor seaboat. But we'll never know for sure since this ship will be scrapped anyway in 1921.
It would be a show of force, but maybe some other nations might not like such an act. In reality, it's just a total waste putting warship materials into a ship that will be scrapped anyway.
Why doesn't it make sense ? Because something like that would be pretty much an act of stupidity.
Walter