Releasing a server-side version is a sensible decision, because not all browsers fully support WebAssembly. Instead of running in your browser, your Blazor code runs in ASP.Net Core, using SignalR ...

It's been a long time coming, but .NET developers can now finally enjoy a full-stack, production-ready Blazor framework for creating web applications with C# instead of JavaScript. At Microsoft's big ...

Microsoft works to improve web app performance with Blazor server-side rendering and streaming rendering, Blazor WebAssembly runtime improvements.

Server-side prerendering for Blazor WebAssembly apps also requires an NET Core element on the server, which negates any free hosting options. Restricted runtime.