The value of a share typically comes from the productive assets the company owns. If you buy all 468 million shares of QSR, you get all the restaurants, the brands, the vendor relationships, the employee relationships, the customer relationships. If you have a smaller fraction, you have a smaller fraction of that, plus you are entitled to a share of the profits generated.

But if you buy a Bitcoin, you own no productive asset and therefore are entitled to no profits. At one point the theory was you could trade it for something useful, like other currencies. But it's a pretty bad currency, so people mostly have stopped pretending it is useful for that.

There are answers to the rest of your questions, which are complicated and depend on exchange and jurisdiction, but people can look up the details if they want.

As an unaccredited investor, your investment funds can only be accepted by publicly traded corporations (with all the legal protections and reporting requirements that entails). Investing in GameStop is definitely riskier than putting your money in a savings account, but fraud is substantially easier in a totally anonymous and unregulated market like the crypto sector.

I mean, just think about how hard the Enron execs had to work to defraud their investors! They had to come up with a novel scheme to hide losses, collude with their accountants to avoid detection, and some of them even had to spend some time in prison. Yesterday, I read about an NFT scam where the anonymous developer just transferred funds to his personal wallet and then disappeared.