What’s the main differences between usages of Blazor and typescript with JS framework on client side of asp.net core site?
Typescript / JS / C# are language
Angular / React / ViewJS / Aurelia / … / Blazor are all web framework with one goal “make a Single page application”. There goal/usage are the same.
Blazor is basically a C# (or webassembly if you want) version of angular or react.
There is also the possibility to use a server side blazor that work on the server. With this version the loading time is quicker and navigator support bigger. But the server usage will grow.
For the comparison you should try it youreself. Blazor already offer a lot of feature (Authorization / Localization / Testing / Trimming / …). As Front and back are in .net blazor will allow you to share some code. But it is the first release version and not a fork so you should wait Feedback in a year or two to depend on it for a big project. It’s only my advice.