Peligroso Patzer: After Tartakower’s <4. … d5>, Alekhine gives the following comment:“This variation has been tried out repeatedly by Dr. Tartakower with intermittent success. Its sole advantage is that it renders Black’s position difficult of access; its disadvantages, on the other hand (condemning the queen’s bishop to passivity and weakening the black squares in a manner hardly to be remedied), are much more weighty. More alluring appears to be 4. Bb4+ 5. Bd2 Bxd2+ 6. Qxd2 Nc6, followed by … 0-0 and, eventually, … d5 and … Bd7.”
source: <New York 1924>, by Alekhine Alexander, Russell Enterprises, Inc. ©2008, at p. 224.
There are two things in Alekhine’s comment of which I cannot make sense, to wit: (1) Why would Black want to exchange his DSB in the first place in this structure; and (2) Having done so, why would he play … d5 (rather than ..d6) in preparing the LSB’s development? (I realize, of course, that if Black refrains from playing <... d5> indefinitely we are no longer in the same variation, and perhaps Alekhine was saying, if you want to play the Stonewall, this is the move order to follow; but this gets back to question #1, above: if Black is going to play the Stonewall, why trade the DSBs?)
Can any one out there provide elucidation of Alekhine's point?