Nothing compares to how nicely integrated Blazor is. I don't have to waste my time "turning on my JavaScript brain" and thinking of all the nuances, I was just doing C# for the back-end logic, and I can continue using C# for the front-end. I can continue with the same mindset and skill set. It's drastically more productive.
I can take any developer who has zero front-end experience but tons of C# experience and have them building very capable web applications, and nobody using them would tell the difference.
WASM was birthed out of trying to make JavaScript even faster.