The worst part of using something like Coinbase is having to do yet another bank transfer, waiting for it to clear, doing KYC/AML yet again, etc etc for what most people is just to buy one or two single asset (BTC or maybe ETH probably). Instead just click buy in Robinhood or Schwab along with everything else.
A friend of mine works for one of the major crypto firms and they're starting to deploy algorithmic trading bots on their own exchange.
The spreads on these markets can be diabolical
If interest in tokens and altcoins wanes, Coinbase may be in a weak position.