is either a mistake or a trickmove. It is tempting for white to cut at . But white should simply play a kosumi at .
We can understand the ineffectiveness of by changing the order of the moves(tewari). If Black played first (instead of ), and white answered with . In that situation it would be bad timing to play . looks more like a big endgame move from that perspective. In other words, this position is not efficient for black.