The main target is enterprise software systems and web backends. Asp.Net is a very mature framework for Web APIs and MVC applications.
Entity Framework is a decent ORM solution supporting several popular DBs with tools for code generation and migrations, and LINQ is a complementary query language that is useful for in-memory collection operations as well as db queries.
And I think the largest value is in the NuGet software library ecosystem, things like MassTransit for service bus and queue communication and many many others.
It’s a well-supported ecosystem of first party and third party software with a lot of modern features, but definitely still in the realm of managed runtimes so not a competitor to C, Rust, etc.
*ASP.NET Core
That being said, WhatsApp is like the authorized garage where you know that you'll get the service which is officially recognized (by the government) and will keep your car's value "at its best", but which screws you over in so many ways.
Everything else is somewhere in between these two platforms.
End-to-end encrypted group chats are currently in the works.
Source - https://t.me/durovschat/518625