There are actually more features on IOS that aren't on the web version than the other way around, One is the approach grid. On the web version we have to use either the pitch or chip view to get the same results. And if you forget to change back then to make a poor shot.
The other is something that many many of us have almost begged for. The ability to share scorecards.
And many of the features on the web version were on both mobile versions first.