They seem to be pretty effective when it comes to leaving a bike in busy area in broad daylight. My anecdata is that the only time my bike was stolen was when I

They seem to be pretty effective when it comes to leaving a bike in busy area in broad daylight. My anecdata is that the only time my bike was stolen was when I failed to use the D-lock right (just locked the wheel, oops) whereas the properly-locked bikes around me were all still there. Leaving it overnight or somewhere out of the way, though... yeah, a different story. Threat model, as you described.