The idea is to unify the development process and tooling on the front-end and the back-end, without suffering from poor performance and constant unnecessary roundtrips over the network. Not to mention, a significant number of people strongly prefer C# to Javascript (and even Typescript).
If those two things never bothered you, then you might not understand the benefit, and you can continue to use what you like.
In practice, sending the .NET libraries over the network is the major burden of the approach Blazor takes, since the first load will be slow and bandwidth-intensive, even though everything will likely be cached for subsequent visits.
However, as the WASM tooling and standards improve, the library sizes will shrink, and less libraries in general will be necessary to accomplish stuff that has been solved at the level of web standards.
There is also server-side Blazor which doesn't use WASM components but instead uses SignalR to do client/server communication. Both are compatible with the same code base (and components). Server-side Blazor still has overhead but it's different from having to send the .NET libraries over the network.
If those two things never bothered you, then you might not understand the benefit, and you can continue to use what you like.
In practice, sending the .NET libraries over the network is the major burden of the approach Blazor takes, since the first load will be slow and bandwidth-intensive, even though everything will likely be cached for subsequent visits.
However, as the WASM tooling and standards improve, the library sizes will shrink, and less libraries in general will be necessary to accomplish stuff that has been solved at the level of web standards.