Generally agreed, and out of curiosity I just looked through some fairly new code I have that's pretty heavy on C# 6, and only found a single instance of two null conditionals being used:

    Assert.That(r.Exception?.InnerException?.Message, Is.EqualTo("Exception result"));

Next closest thing that shows up a few times is coalescing to a default value:

    config?.OutputName ?? DefaultConfig.OutputName

Some other examples that show up a lot:

Invoke Action<> or Func<> that may be null or unassigned (this works for Events as well):

    actionHandler?.Invoke(value);

Extracting a value from a LINQ expression on a list of container objects (this one is actually from a unit test where it's explicitly only expecting one item):

    items.First()?.Data

Easy way to do a Coalesce on a specific property value in a collection:

    items.FirstOrDefault(item => item.Data != null)?.Data