Genuine curiosity

Someone step in if I’m missing the point here.

If a person buys 70,000$ in btc etf from MicroStrategy.

And he (they), then take that as collateral. And buy 7M in btc. Using the 10% as a collateralized asset.

And he/they then own 10x the deposit amount in btc. Which then accumulates. And this happens on the billions of dollars scale.

(Aside: this assumes 10% deposit. Some multi-billion $ companies get 2.5% deposits)

Would people not be paying him to be a self custodian, actually owning the referenced btc. Whilst the “investor” in the etf owns only the etf fund share ? (Risk claims vary)

I feel like I get exactly how this works. And the etf share purchasers miss the absolute entire point of this. . . .

Please sort me out if I’m missing something.

Other than the leverage, exponential gains, and actual custody. Not including the fact that they can then future borrow against the capital they have already borrowed to get. Leveraged again.