TL; DR
Qualitative and quantitative data are both crucial.
Debates over which is better hold back progress but are sadly all too common. Some "qual" and "quant" people even pay lip service to the other "side" but still do nothing at all to embrace the other kind of data (and people) actively.
The solution? Truly value and then use both, typically sequentially, first qual to understand reasons and then quant to learn nuances at scale.
