The one downside to this is that the B and D trains do not stop at 23rd so you will be waiting for a subway longer on average.

I also find that walking out of 33rd street station is easier if they open both sides of the train, which they usually do. Just switch to the second side of the PATH doors they open and you will not have any any bottlenecks through the turnstiles.

But you are correct that the walk is a bit shorter. Also note that there are multiple ways to get from PATH at 33rd to the BDMF trains, make sure you are going to the right side when you exit the PATH turnstiles - do not walk the hallway on the left - the stairs on the right are much faster. It took me a while to find this shortcut.