My point is: why experiment? Why risk this?

It's a Type R thing.

That would be "R" for risk-taking behavior- of any type. Sky-diving, free climbing, cave diving, escape artistry, taking a skateboard over the high side into an empty swimming pool, hacking a high-security computer server, doing experiments with explosive or toxic chemicals, poaching on a guarded country estate, inventing the airplane, racing motorcycles, going on walkabout, writing an iconoclastic musical composition, walking a high wire without a net, sailing arond the world solo- or seemingly off the edge of it, like Magellan (who didn't survive the voyage he captained- and only about 10% of his crew did)...

Why do it, if it isn't driven by necessity, and the odds of living a longer life with less pain and fewer contusion, broken bones, and other physical complications?

I don't think that question can be answered definitively or objectively. But, as conjecture: pushing the edges is where new stuff happens. It's exploratory. And the results have been known to benefit more than simply the risk-taking drives of the participants.

I think it's worthy of note that most risk takers, especially those who take the greatest risks and who involve themselves in risky behaviors simply for the sake of taking a risk, are males. There are exceptions- some snowboarders and skateboarders hurtle to mind- but it's mostly a male behavior. And some males seem to have the tendency almost as a compulsion- as a rule, they're the ones who push the envelope of risk-taking stunts.

For what it's worth, males who engage in risk-taking behaviors very often find that they have more success at attracting sexual companionship. That's especially the case when the behaviors are performative, either as physical feats of skill or as artistic endeavors.

So that's one plausible explanation I can supply, in the general sense.