Valuation is not just what you see on face value. It also includes assets, working tech, and other stuff which evaluators would be looking at. Coinbase, being one of the first movers of centralized exchanges and still at it even after almost a decade tells you a lot about their reputation plus the value that they have put into the company. Also, Binance, being one of those 'cowboy' exchanges that does not want regulations touching its platform is simply a no-go for investors with deep pockets, as they don't want to endanger their investments from such a platform that is raking up a lot investigations, complaints, and the likes. If you're already risking money on an investment, why increase the risk even more on something that is always being chased by regulators and always on the edge of being shut down?