Who the heck is society? That's just us. But we don't come together and decide like that, so I don't think society exists in the abstract the way you think it does.

It's more like this is how reality is. You've probably never been a trader, most traders lose their money, it's an extremely risky profession. For every win you hear about there are at least 10 losers.

At the end of the day the activity of traders readjusts the asset prices on ongoing basis closer to their true valuation. The more trading occurs the more precise the price is. Without enough trading activity an end user might be forced to overpay for an asset.