I've seen both those films.
Imagine that your "job" is to "gamble" the bank's money (share capital, client investments, borrowed money, etc.) and you can have pretty much carte blanche on what you do, how you do it and so forth then that would be the (now theoretically banned) proprietary trading desk, the sexiest part of the pointy end of the investment banking trading floor.
This is not merchant banking or hedge funds (the successors to proprietary trading effectively) or deal making etc. this is pure out and out trading for profit.
So yeah, when the Big Short comes in and starts talking about mortgage backed securities, collateralised debt obligations, various put and call options and all the other derivatives on the back of synthetic and non synthetic derivatives then yes, it is right and yes, it did happen, and it happened in much the same way as you see in the film (though over a longer period of time and then very fast, which was depicted).
Margin Call should have been so much better but I forget that the target audience has no idea what we are talking about or the language we use or the size of numbers we discuss. A bar is a million, a yard is a billion, etc. but yeah, the theory is right as is the execution and the culling of people did happen. One old timer said to me that you shouldn't worry about getting canned as that is how people paid off their mortgages, with the compensation 😆
In certain quarters, the public would be horrified and shocked beyond comprehension and if they knew that the people in government making decisions knew so little then they would be scared even more.
Unless you are right in the eye of th storm, you cannot know what it is like. For me, that first came with the overhang of the UK listing of Billiton by Kleinwort Benson where we were losing up to £100,000,000 a day at one point.
That is pretty focussing !