> I'm not 100% familiar but doesn't this app allow you to re-invest your paper gains without actually having anything material
I can't parse this sentence.
You can 'reinvest' non-settled funds. This is the definition for any margin account. "Paper gains" is usually in the context of paper trading, which the app doesn't allow. So this doesn't make sense.
Your link is not working for me, but the case for that customer was a lack of understanding, he didn't really owe 730k. It was a temporary balance. Which is the kind of thing you need to understand if you are trading options.
> We're all told to invest, so it's only natural for millennials/GenZ/etc to want to do that. Everything costs money,
Robinhood is mostly used for 'gambling'. If you want to invest, you should open a boring account in Vanguard, setup automatic deposits in VSTAX or similar (or manually on VTI), but otherwise forget about it. That's investing.
Playing around with short term market fluctuations is either trading or gambling.
> so if you can "make more money out of the money you already have", then that's quite appealing.
And yet that's what people do. If you are not doing the same, you are doing yourself a disservice.
This concept doesn't only exist in stocks. For instance, take a savings account. It appreciates over time. The reasons why are left as an exercise to the reader.
> As if creating money out of money makes any mathematical sense.
But it does. It's not about money creation, it's about wealth. Wealth is being created all the time. This is why the long term market tendency is always up. The moment we stop creating new things is the moment this will stop.
Since you are on Hacker News, read this, by Paul Graham: http://www.paulgraham.com/wealth.html
> I think in the end, all these "investment" apps are really just shuffling money from users. How else can you "make" money without taking money from someone else?
Congratulations. You have discovered trading. Someone buys, someone else sells.
Note that this is only a zero sum in the short term.