Is Having A Roth IRA in RH vs Fidelity or Vanguard bad?

I was at work talking to one of my older coworkers and I told him that I opened a Roth IRA in Robinhood and he just started saying, “no no no no that’s bad. They keep ‘the float’.” Could someone help me understand what this actually means? I just opened it about a week ago and I am having second thoughts. Obviously this is just one person’s opinion, but I just wanted to check with other people on this.