Main difference between Property-Map-Value method and Property-Map-ValuePair method is
Property-Map-Value calls a Rule-Obj-MapValue once, and Property-Map-ValuePair calls it twice
Property-Map-Value can call a Rule-Obj-MapValue and pass a single row input, and Property-Map-Value-Pair can call a Rule-Obj-Map Value and pass two row inputs
Property-Map-Value can call a Rule-Obj-MapValue and pass a single row input, and Property-Map-Value-Pair can call a Rule-Obj-Map Value and pass a single row input and single column input
Property-Map-Value can call a Rule-Obj-MapValue and pass a single row input, and Property-Map-Value-Pair can call a Rule-Obj-Map Value and pass multiple row inputs
This is a duplicate of question 146856. The Property-Map-Value method takes a single row input to evaluate a 1D map value, whereas Property-Map-ValuePair takes both a row input and a column input to evaluate a 2D map value.