>>76588966 (OP)
No, lifting in general has almost nothing to do with posture and worrying about posture for the most part is just retarded cope. If you actually have something like scoliosis then you can worry about it.
Dips don't really work the back at all, except for the lower traps technically since you depress the scapula.
It biases the triceps and lower chest more than a bench, with the relative emphasis on them getting more pronounced/extreme the more vertical your pressing angle is. If you stay in a very straight up-and-down line doing them it is the best triceps and sternal head of the pec compound exercise.