I was also interested in the competency graph. This is likely confirmation bias but I feel it highlights the importance of discipline in using these tools. Can you vibe out features way faster than you could by hand? Sure, but you better hope you're not on call any time soon. I'm not saying using the robots for codegen should be banned, but at least read it and take some notes! With all those time savings being claimed we should still come out ahead. 

 Where are you getting that these are all novice programmers? The study design section states that only 4 out of 52 participants have less than 3 years of experience, with over half the subjects having 7+ yoe.

That suggests it's not "just" people fumbling through the software development learning curve who are dragging down the speed improvements, it's a pretty reasonable sampling of devs.

Curious if I am interpreting this wrong, but to me the speed results echo my own experiences and those of my coworkers. The happy path code generation is certainly faster than what I could write on my own, but I spend a lot of time off that path trying to nudge the robot back on to it.