I play chess and have boxed and done martial arts, although never together in the same ring.
I found chess more destructive than boxing — it serves little to no cardiovascular benefit, and can be hugely addictive. (Bullet chess and competition play can readily take over your life, and I've seen careers and relationships destroyed by it.)
The fittest people I've ever met have been boxers. Yes, the risk of head trauma and eye injury during fights is higher than even MMA (https://www.ncbi.nlm.nih.gov/pubmed/26327287 ), and every fighter must weigh the risks of that with what they gain from the sport.
> Getting used to boxing means you get used to seeing violence and it
> doesn't hurt so much any more.
(1): Getting hit still hurts.
(2): Seeing people getting hit outside the ring hurts more, because you're more aware of what they're going through.
(3): I've seen boxing (and martial arts) restore respect in people and their communities; kids transformed from roaming the streets to training at the gym every day (not always in the ring; many days just working out).
It is easy to see two people knocking the crap out of each other in a ring and assume those exchanged blows embody everything the sport has to offer, but like many contact sports there are more positive side-effects than bloodied faces and the normalisation of savagery.