"Ride sharing" is a taxi service that does not provide worker benefits, nor legal customer protection. It's a scheme to avoid any law and responsibility that applies to a taxi sevice.
Fintech, in the same vein, is a scheme to avoid any law and responsibility that applies to banking and finance.
Robinhood's promise to actually hold my stock is exactly the same as my bank's promise to hold my stock, or my money, or anything. Fractional reserve, baby, and with current reculations, the fraction is defined as basically nothing. I don't see how a bank run or any other similar problems are any different on Robinhood than they are on a traditional banking/finance institution.
All of the fine inventions of derivates, subprimes, CDOs and so on were invented by good ol' traditional finance sector. They don't get to lecture anyone on risk. We are still living in the 2008 world they created. Enough nuclear sludge to create a nation of Toxic Avengers. Lawless country, and nobody bats an eye. Now the new guys are avoiding responsibility via techo-mambojambo, instead of lobby-mambojamobo, and suddenly there's the end of the world.