The RooStats::AsimovSignificance, RooStats::PValueToSignificance and RooStats::SignificanceToPValue helper functions are lifesavers as they provide accurate estimates and reduce mistakes (factors of two, etc).
I was looking around and was wondering if there are also helper functions that encapsulate other RPP formulae, e.g. the frequentist confidence intervals, described in the RPP 40.4.2, in particular Eqs. 40.77a, 40.77b, 40.78a, and 40.78b.
These are not hard to do and can be contributed if there are no objections and some naming guidance.
For the Poisson there are the methods in TH1, TH1::GetBinErrorLow(bin) and TH1::GetBinErrorUp(bin). If you want a free (static) function, you can use ROOT::Math::gamma_quantile and ROOT::Math::gamma_quantile_c as done in the implementation of these TH1 functions. Maybe we could add in this case a more convenient function for the user to compute the Poisson interval