The JSON extension methods are "opinionated" in that they force you to use JSON.NET for serialization and the default serializer settings that I've included. I don't know that we should recommend these extensions as the "best" option, but rather "an" option. If a user is content to rely on these basic methods, then they would be sufficient. However, there are many users who will prefer other JSON serializers or other class-to-document mapping rules. So rather than attempt to address all JSON concerns with the API, these are convenience methods, which is why they're extension methods. Extension methods in .NET allow a user to treat method like a class method, even though it's not defined in an object's interface.