Devil Jin has a very solid close range game due to his jab. Putting out one let's you confirm whether or not it hits to use the +1 or +8 to continue your pressure. Using 1,1 let's you hit-confirm into 1,1,2 which gives him MCR okizeme.
The however his quick mid checks aren't amazing df+1 and df+2 are good, but don't give a lot of reward on hit. Therefore using his ws4 is a strong choice as it gives +8 on hit and allows him to frametrap with b+4 and d+3.