Acquired Bitcoin, whether held directly by individuals with self-custody, or held by Blackrock or Fidelity to cover their ETFs takes those Bitcoins out of the available supply which increases Bitcoin scarcity. The end result is the same, fewer coins available - and that makes the price of BTC go higher.
BTW, Fidelity self-custodies their Bitcoin in-house unlike Blackrock, who uses both Coinbase and Anchorage as custodians.
What this really shows is that demand for Bitcoin is flowing from both sides. Retail holders remove supply through self custody, while institutions do it through ETFs that appeal to traditional investors. Combine that with lost coins and long term holders, and the float keeps shrinking year after year. Instead of weakening the case for direct ownership, institutional accumulation makes it stronger, because scarcity only increases.
Bingo! You got it - spot on!
Additionally, with greatly increasing adoption in all areas, including retail investors, countries' reserves, private companies, etc., this will only continue to move the price higher and higher in the future.
Bitcoin will climb quickly much higher in price just like the stocks of Apple (AAPL) and Amazon (AMZN) for example have done once the public and financial institutions/firms see the increased demand for BTC and people adding spot Bitcoin ETFs in their brokerage accounts.
For example, I bought both AAPL and AMZN at $5 about 15 years ago - now they are both 46X higher at $230 with financial institutions and retail investors buying up more and more shares all the time.
I would not bet against BTC, now at ~$115k, increasing 46X (like AAPL & AMZN has done) over the coming 15 years, which would be $5 million per BTC in 2040. This $5 million price for Bitcoin is actually what a lot of experts have predicted it will be in 15 years in 2040...
And with me being an experienced 'investor' and not a trader, I still own a lot of shares of AAPL and AMZN!
What's also nice is people can buy just 1 share of spot Bitcoin ETFs (IBIT or FBTC), or even a fractional share and add more on a weekly or monthly basis if they desire.
For example. one share of Fidelity's FTBC today is about $100 which represents about 0.01 or $1,150 worth of 1 BTC which is ~ $115k. Some brokerages like Fidelity even allows fractional shares so a ½ (.5) share of FBTC can be bought for just $50.