Binance gets less than 10 million dollars of volume is a great way of saying binance is making over 2-3 thousand dollars profit PER DAY, and we all know they are making much more than with all other stuff that goes on with that website, they are probably making above 10 even 20 thousand dollars in profit every single day and that is why they are more popular than any other decentralized exchange out there.
Plus, binance literally made their own DEX which I still think it is not fully DEX and combination of centralized and decentralized, but even with that out of question, decentralized exchange they created didn't get all that much volume. Why? Because people do not really want to use it, as long as there is no community behind any DEX, we will not see any successful one.
It all matters with peoples choice and we have seen on how decentralized exchanges do perform in terms of user counts.
I agree on what other said about the reason why people doesnt like to use these platforms because of the lacking of fiat features.
Dex cant offer such thing thats why we can see the difference when it comes to demand.
We have seen some few good Decentralized exchanges though but still not really the same with exchanges that we do know today.