What are the reservations about the functional approach of the C # chain? What to do with ifs?

Question

I recently watched the Pluralsight course "Functional Programming in C #". And rewrote some methods in my hobby project. Now they look like this:

public override CommandLineResult GetResult()
{
    return Disposable.Using(new IndicatorRepository(), repo =>
    {
        return repo.AddOrUpdateIndicator(Indicator, Value, DateTimeExtensions.LocalNow().Date);
    })
    .Map((p) => new NumericIndicatorRecorderedModel()
    {
        Id = Guid.NewGuid().ToString(),
        DbActionPreformed = true,
        IsRewritten = Convert.ToBoolean(p),
        IndicatorName = Indicator,
        Value = Value,
        ValueDate = ValueDate
    })
    .Map((model) => new CommandLineResult()
    {
        ActionName = "~/Views/CommandLine/_clresult_NumericIndicatorRecorderedModel.cshtml",
        Model = model
    });
}

There is something beautiful in this chaining approach (I removed the use with a one-time class, at every step I have expressions, not instructions, etc.).

But there are questions:

• Doesn't this approach cover some dangers? and what are they? (for example, not difficult to debug)
• What do people usually do in terms of chaining if they need to branch out the code flow? An open circuit somewhere? Write "map-if" functional extensions (would this approach create spaghetti code?)?

UPDATE: a more specific question on this issue

- :

        public string GetResult(bool param) {
        if (param) {
            return MyClass.DoOneWay(p =>...).AlsoDo(q =>...).ToString();
        }
        else
        {
            return MyClass.DoOtherWay(p =>...).AlsoDo(q =>...).ToString();
        }
    }

if-helpers, :

        public string GetResult(bool param)
    {
        return MyClass.DoIf(param, p => ...., q => ....).AlsoDo(q =>...).ToString();
    }

, , true/false? "" "" ?