I personally always carry the half mills for wherever I am going. There is nothing worse than having to leave CAS for whatever reason (ATC, ice, Transponder problem, landing at a non IFR airfield etc) and having to navigate VFR (or rather fumble around VFR) with an airways chart. Admittedly a Citation is a bit different to the PA32 and I guess there are very few events which would lead to a Citation being kicked out of CAS.