Coinbase has created it's own layer 2 chain. And all the exchange and the ecosystem transactions are routed through that chain. Most of the dApps specific to the coinbase are hosted on the Base blockchain. It takes the stack out of the Optimism chain. And so the performance is similar due to the features being offered for the layer 2 in that stack. They recently reached the daily trading volume of $356M. 

Not just this they also reached another milestone of keeping up with the low fees on their chain. Considering they are making use of the Optimism stack they are bound to stay on the low fees. And that would also help their chain overall. It would be interesting to see how the future for the coinbase's BASE chain be if such good performance continues for long term. 

Coinbase is likely to turn the chain and the exchange into the SEC compliant chain and the exchange. Which means they are moving away from the DEFI scene and are going to be everything KYC in near future. So we have to think of them as more corporate type of the structure in near future. You can expect them playing role in the CBDC usage on exchange too. So there is another addition to this changing scene of the Base blockchain. 

I personally am not a fan of Arbitrum and BASE the reason being both are kind of loaded with VC manipulation and also they have enough dApps and the projects that would only make the overall ecosystem lag more in terms of the features and the projects that would change the direction of the variety of the DeFi project if they happen to collide with systems like Base and coinbase. 

Let's see where this progress of BASE blockchain goes and how coinbase improves further.