For us it was a mixture of multiple things: It’s a very mature library that has been stable over the last years and became the de facto standard in web-based visualizations, where—just as in Rerun—interactivity plays an important role. The predefined forces that ship with it make it very flexible and are easily extensible. Finally, having worked with it a fair amount in the past, personal preferences surely played their part as well.

I’m such a D3 fan that I wish I could follow the creator his current project Observable, but D3 just interests me way more.