I'm 65 & have a cholesterol 164 cholesterol count & 3:1 hdl/ldl ration. How might I benefit having a high-sensitivity CRP test?

Overall CVD risk. Your hdl/ldl ratio 3:1? Not reverse? That is highly unusual especially if you are not already on medications like a statin. It would be helpful to know your actual LDL and hdl. In any case, if you are at increased cvd risk for any reason, checking hs-crp may help you in deciding whether starting or upping your lipid management. If more than 2.0, you may be at increased risk for cvd.
LDL Not Cholesterol. Little, hs-crp low value vs. Ldl & HDL which are lipoproteins, i.e. Protein particles which carry all fats in the water outside cells. Ldl is always in nmol/l, best <700, HDL in µmol/l, best large-hdl >10. See NMR particle test, <$100. Ldl particles are the primary driver of ds. Cholesterol is a fat made by every body cell, not best test, ldl-c calculated, not measured, & often misleading but↓$.