More of a VS thing but the fact that you need to have copilot to have a good intellisense experience.

Let's say you are defining several JsonPropertyName attributes for your properties, while writing:

[JsonPropertyName("postId")]
public int PostId { get; set; }

Base intellisense will propose something completely unrelated for the property while with the github copilot extension, it will automatically recommend the correct property PostId after writing the JsonPropertyName attribute.

Same thing if you are defining Validators in the same file as the validated object:

// Post.cs

public class Post ...

public class PostValidator: AbstractValidator<Post> ...
}

With the copilot extension, after 2 or 3 files, it will automatically propose a validator class for autofill. Default intellisense? You got to type it out manually for every file.