Attribution is a huge pain point, even for the biggest businesses with access to abundant resources (I used to work for a digital analytics consultancy—we had clients like GoPro, Yelp, and VISA). I think brand awareness efforts, although hard to measure compared to Facebook, SEM, or display, absolutely inform purchasing decisions, and likely is a bolster to other more metrics-driven campaigns. I’m almost feeling defensive writing this—because I know, and try to prepare for, the assail on the softness of this position. Anyway, I think you nailed it when you said you couldn’t quite put your finger on it. That’s brand.