It is a concern because it allows that one pool to alter transactions in the blockchain, while nodes create the rules avoiding a 51% attacks also helps keeps bitcoin decentralized.
Discussion
A 51% attack is financially unfeasible, and the only country that could have done it was China (I think they had around 65% of the hash rate). Instead of seizing the machines, they just kicked out the miners. Kkkkk, they are idiots. They'll regret it bitterly; they probably lost the chance to become the most powerful country in the world! Thank God they lost that opportunity, right?
China will absolutely use any opportunity they can to seize more power, and control.
I don't see how sending the blockchain into chaos, which would inherently lead to plummeting prices, would be in China's best interests. Given their holdings and engagement with the Bitcoin network, it seems like their best interests are served by ensuring the stability of the blockchain.
China benefits from controlling the Bitcoin network to de-anonymize any privacy preserving tech in Bitcoin, they can subtly scoop off fees, or manipulate blocks to pay fractional amounts towards them, or they can shut it down completely by forcing the blockchain to become worthless.
They can also use Antpool, and KYC processes to keep track of every transaction on The Blockchain, and associate with known entities (usually citizens who comply with laws).
Even if you say this is FUD, it's not because Price Bros don't care about the network as long as their fiat bags keep going up.
Most people don't actually use Bitcoin, they just hold paper derivatives of it.
Either way, China wins, they get to profit off of Bitcoin's fiat speculation, and appreciation, or they shut down one of the biggest threats to their global order.
FUD. Those who don’t truly use Bitcoin will learn the hard way. China missed its chance, it’s over. Next!
And if they used that power to cheat, it would have resulted in a fork that no one else used.
All these problems ultimately lead to potential short-term dips and reorgs, while the nodes will always pick the most decentralised original chain by default.
Storm in a teacup.