Questions about undocumented Option.Action vs Command.SetAction

Hello - I am trying to familiarize myself with this library and I noticed Option.Action https://github.com/dotnet/command-line-api/blob/main/src/System.CommandLine/Option.cs#L131 but it is not documented anywhere (as far as I can tell) in the MSDN docs here: https://learn.microsoft.com/en-us/dotnet/standard/commandline/

Is this feature deprecated? If not - are there examples anywhere of how it can/should be used?

I find it confusing when compared to the well documented `Command.SetAction()` examples - are these two action delegate systems at odds or complimentary?