The US is playing double gaming at this stage. At one side SEC Charges on Binance and Coinbase and on the other side SEC are in the favor of approving Blackrock spot ETF.
Cons:
People will not hold real btc because ETFs could not be called real Bitcoin holders. Etf trader are not holding any btc in their wallet. An ETF is just a contract in the form of paper.
If prices increase then these big asset managers can dump the market to stable Price. This will decrease the interest of crypto users. In short the growth in price will be very slow just like gold
Bitcoin will not remain totally decentralized and the Government will be able to control it.
They also said that we will not be bound by the rules of Satoshi which he mentioned in whitepaper that's mean in case of Bitcoin fork they can choose any chain for their price backup.
1) I don't know why you think the SEC is favoring approving the Blackrock ETF. They are very clearly going to reject it just like they've rejected every other BTC ETF proposal. I don't understand why people are so hyped over Blackrock. The head of the SEC hates Bitcoin. This ETF will not get approved. As long as Gensler is head of the SEC there won't be any Bitcoin ETFs. I can't even imagine where you got the idea that the SEC is favoring approving Blackrock's ETF. The only statements the SEC and Gensler have made thus far about that application have been negative. There is no double gaming, the SEC is very anti-Bitcoin and anti-crypto. It is a very obvious single-sided straightforward game they are playing.
In terms of the cons:
1) Anyone can still own Bitcoin. Only the people who don't want to own Bitcoin but want to use it purely as an investment property will buy the ETF. I don't see any problem in this. Sure none of those people will be 'using' Bitcoin, but it'll still increase adoption of bitcoin as a financial asset, which will increase the price of Bitcoin, which will get more people interested in Bitcoin, which will increase adoption of Bitcoin more generally, including people who want to actually own and use Bitcoin.
2) You don't seem to understand what an ETF is. An ETF is not a financial firm trading Bitcoin (and thus being able to dump it whenever they want). An ETF is a firm buying Bitcoin on behalf of their clients. The firm cannot just dump the Bitcoin in the ETF to keep the price stable. The people who invest in the ETF would have to sell their ETF shares for the firm to sell that amount of Bitcoin tied up in the ETF. Has nothing to do with the price appreciation of Gold.
3) Don't see how you are going from an ETF existing to Bitcoin not being decentralized and the government controlling it haha. I can't even imagine how you made that leap of fantasy, but an ETF has nothing at all to do with Bitcoin's decentralization or govt controlling it.
4) I keep seeing this idea of Blackrock forking Bitcoin. I don't know where this idea comes from. Did Blackrock say something about forking? Regardless, Blackrock has no more nor no less ability to fork Bitcoin than anyone else - meaning sure they can do a useless fork and create an altcoin like anyone can, but nobody can fork Bitcoin away from itself, so I don't see where their fear comes from. Nothing about a financial firm having an ETF has anything to do with being able to fork Bitcoin away from itself.
That should pretty much dispell all of your concerns. But anyway, the Blackrock ETF is obviously going to get rejected and there won't be an ETF approved until Gensler is gone from the SEC which is 3-4 years from now so all this talk about ETF's is kinda silly and no different than all the other times people got excited for ETFs over the past five years.