I know it can seem like a dumb question. Who cares about dips when you can do a planche, etc. I'm also well aware of the nature of specificity and how it relates to training at different joint angles and such. I know from looking at it, training back lever would likely have a greater effect due to joint angle specificity. I'm just wondering.
For the record: I've cut back dip work in the past, and substituted one day a weak pseudo planche pushup work, just to see what would happen. Made progress with PPP's and no extra reps were gained with dips. Did feel a little better support around lockoff zone, but that was about it.
Now, I'm wondering what would happen if I kept my frequency the same for dips 3x a week, but did planche work early in the morning in addition. Not too much extra work (not to failure, keep the workload moderate), but enough to make progress in planches.