My own experience is that it _might_ speed up juniors (and even that, I'm not convinced about). But juniors make up a tiny part of the overall throughput, I am easily 10x faster to do anything than they are. So a 10-20% productivity boost for juniors is pretty much negligible for the company.

For myself, everytime I try to use chatgpt it completely fails to be helpful, for the same reason that stackoverflow also fails: the problems I have as a senior are too specific or too complex. Every single time, querying an LLM ends up being a waste of time.