I don't think that's a fair comparison in saying it's doing the job of both just because coinbase self regulates which coins it allows. Their markets and pairs

I don't think that's a fair comparison in saying it's doing the job of both just because coinbase self regulates which coins it allows. Their markets and pairs are based on internal risk calculations. DOGE coin was allowed relatively late onto coinbase. Monero is still not supported on coinbase. Schwab does similar with penny stocks and you have to do an interview with a trader in order to be able to do naked calls/puts or advanced straddles as well as trade on margin. Schwab will help you make otc trades on penny stocks that aren't listed on the main exchanges. Not listing Monero is definitely not a good financial decision. That's the currency darknet markets are shifting to. Monero also crashed along with BTC and ETH, it doesn't look decoupled. And crypto markets haven't meaningfully decoupled from the securities market either.