I have mixed feelings about this - on the one hand, it's giving an incentive to working on the "boring" stuff that devs prefer not to do, on the other hand, it'

I have mixed feelings about this - on the one hand, it's giving an incentive to working on the "boring" stuff that devs prefer not to do, on the other hand, it's something that can be gamed and result in poorer code quality (patching the symptom). Also, it seems like the company focus shifted to reducing bugs and general code quality. That probably has something to do with the huge shift in productivity as measured by bug count.