A priori they look as pure parasites, but somehow a prioris use to be wrong.
Interesting debate while price go sideways
Having traders aka. "the market" discover what something is worth is the alternative to setting prices via central committee.
BJA used to talk about this when he was calling btc traders "decentral bankers". Their job is to buy when they feel like the thing is undervalued and sell when it is overvalued, providing liquidity. The ones who are better at this end up with greater means to influence the price.
So much for theory. In reality we have things like insider trading, government interventions and price manipulation by cartels going on.
Claiming traders don't bring any value to the table seems incredibly myopic. They are helping to set the price of things in a decentralized way which would presumably seem useless only to someone who would prefer to set prices of things through central committees and whatnot.
You're all talking about the invisible hand. Which not a bad thing in itself. You mean traders are the way for market to regulate itself, which not wrong.
Now think it the other way around, what does happen when a market is ONLY about self-regularization?
I have nothing against the fact that traders gives the value of things, when they ACTUALLY buy and sell things. But they don't, they just bet on rise or loss.
Not even 1% of exchange are real, they're not "value conquistadores", they're just plain parasites because they don't have to use real things to bet on.
Decentralization is good when you talk about real products. When one will really buy 1ton of corn at a price and sell it back at another price. When you exchange 10000 times the amount of good produced in the world, you don't set the value of anything, you just create "value" from thin air.