Musical cognition is loosely connected to attention (maybe disconnected entirely by this metric, music seems special) and spatial memory is irrelevant. So "better dancers" seems a bit myopic, they might be improving their understanding of rhythm and melody in a more general sense.

(IMO the headline-level conclusion of this study is unsurprising - dancing is far more cognitively demanding than gym exercise!)

Cognition and memory are easily measurable brain functions but are not the exclusive function of the brain. As a conserving machine a healthy brain building volume is indicative of improvement in some function otherwise it wouldn’t bother building the volume.

I got into dance a few years ago, and N=1 sure, but the big changes I observed as a result were improvements in proprioception, balance, sense of tempo, and I also gained the ability to deconstruct music in my head, and listen to different parts of it (e.g. only pay attention to the guitar or the drums or the vocals).

Like does this make me better at programming? Probably not. But the skills you gain do have other usages outside of dance, and honestly also kind of enrich life in general.

> Is there a benefit to having the extra brain volume, even if it doesn't lead to improved cognition?

ever seen megamind?