To C# people: What do you think about this?

C# is a language I most enjoy working with. But with C# 8.0 out, we've gain this piece of technology:

Default Interfaces Methods: docs.microsoft.com/en-us/dotnet/csharp/lang..

I used it in no project, and I've never seen something like that in any other language I worked. What do you think? To me, it makes no sense at wall, we just have abstract classes to this kind of job, and the rest we can handle using pure OOP, in my opinion.