Brokerage Accounts: Vanguard, Fidelity, etc, vs. Etrade

Hello, in the course he talks about various brokerage accounts for purchasing and holding your securities. For example, buy a Vanguard fund in a Vanguard brokerage account, etc.

I currently have an Etrade account that I use. I am quite satisfied with it, and actually I have a couple Vanguard funds already. Though I can’t say I know all the pros and cons of this vs. the Vanguards/Fidelity, etc.

As far as I can tell, all these accounts are simply repositories from which I purchase and hold a fund. (With other services and education.)

Is there a difference I am not aware of? Why doesn’t he mention any of the Etrade/Ameritrade brokerage accounts? Am I missing something?

(I have not finished the course yet, so maybe he touches on this at some point).

Thanks for any guidance!