What does .NET Core mean to you?

I recently wrote about my thoughts and tips on moving from Umbraco 8 to Umbraco 9. The massive change in Umbraco 9 is that the CMS is now built on top of ASP.NET Core (.NET 5).
This made me wonder, why exactly am I so excited about Umbraco moving to .NET Core? What does the transition from .NET Framework to .NET Core mean to a .NET Developer?

I can think of a whole host of things in addition to what I wrote in my blog post, but this is what came to mind when I wrote it:

This evolution of the .NET ecosystem has been a liberation in my opinion. You have a choice in operating systems, a choice in IDEs and editors, and the entire platform has become open and much faster.

I'd like to hear from other .NET Developers, what does the transition from .NET Framework to .NET Core mean to you?