There are probably a lot of millennials on here who've just gotten started in trading crypto/stocks, and they might not remember a time when it cost at least $7-8 to place a trade with a broker like E-Trade or Scottrade (now TD Ameritrade). And it was waaay worse years before that when you had to pay a commission that was a pretty high percentage of your trade amount. Somehow Robinhood came along and now I can buy stocks with no commission--that's like a wet dream for someone like me who can't afford to waste money on commissions.
It's too bad Robinhood doesn't let customers deposit crypto into their accounts as if it was cash. They advertise that you can buy and sell bitcoin on their platform, but you're really not owning any of it and I wish it wasn't that way. Pretty sure the US government doesn't want Robinhood to become a money laundering site and thus won't allow them to do that.