Robinhood is a brokerage and you open a brokerage account with them. So those aren’t really two things you can compare. Although, I prefer more traditional brokerages like Vanguard, Fidelity, or Schwab as they have better access to index fund. Betterment is a great option if you want a fancy modern user experience.
Just ETFs as far as I know.
Basically, yes. You can buy Vanguard ETFs (like VT) inside your Robinhood account. Although, Robinhood’s brand seems to focus on picking stocks and trading which i don’t like. But if you buy and hold ETFs with Robinhood the underlying investment will be the same.
Is Robinhood designed to encourage more day trading versus buying and holding?
In my opinion, yes. Which is why it’s not my preference.