Las Vegas is popularly known as the city of gambling because it has the highest rate of gambling activities and highest revenue generated from gambling activities, so in regards to the question you just ask, the city with the highest Blockchain activities should be called the Blockchain city, while the city with the highest crypto/Bitcoin activities and revenue generated from crypto should be also known as the crypto/Bitcoin capital, likewise vice versa to any other
It's true Las Vegas is popularly known as the city of gambling but making it the capital of crypto will mostly harm the reputation of blockchain, showing it's leaning toward the gambling hub of the world.
I think one of the innovative countries deserves the title of capital. That's the reason I chose Singapore.