local prefix index vs global partition index

I am planning to partition the PAY_RUN_RESULTS in EBS 12.1.3 with Hash partition and RUN_RESULT_ID column is going to be partition key and also primary key column in the table.

My question is what difference it makes if i create local prefix index on partition key column (RUN_RESULT_ID) or create global partition index with same number of partition as table on RUN_RESULT_ID column?

Both method are going to create same number of partitions. Does this means local index partition and table partition has same data but global index partition is not similar to table partition?