Shares have a value beyond that, though; they are a share in an actual company, which has assets and generates revenue (hopefully; granted if you’re buying shares in some SPAC merger that might one day produce a flying car or something, that’s not a million miles away from bitcoin). There is a price floor. One might reasonably argue that nvidia is not worth $3.4 trillion (its current market cap), say, but it is clearly worth _something_, even valued purely on assets and yield. Bitcoin has no floor; you are entirely dependent on other people buying it from you for more than you bought it for, because they believe that someone will one day buy it from _them_ for more than _they_ bought it for.
As long as you have a real share, and are not holding an "entitlement" (e.g. a brokerage firm holding your shares in their street name. In that case, you have the right to the economic benefits of the stock, but not the underlying. To do that your name needs to be on the company's ledger. Anyone can request to directly register their shares and hold them directly with the company's transfer agent.
I mean, unless the broker is fraudulent there’s very little practical difference; most people will go with the broker, as it tends to be cheaper. For that matter, most people aren’t investing in individual shares, they’re investing in some sort of mutual fund, so there’s another party that you have to _somewhat_ trust there.
