I believe the prosecution is showing the receipts ...with special attention to the time, to show the jury it took hours to get to TA's house to murder him.
Obviously she was packing a gun. TA didn't own one.
I believe the prosecution is doing an excellant job of showing a cold, calculated, premeditated murder.
Jodi went to LA first to see her friend who had a baby, or so she said. I'd find it hard to believe that she didn't actually visit the friend since she told Ryan about it before, and Detective Martinez after, the trip.
I think showing the absence of receipts in AZ is to demonstrate her premeditation by leaving a trail from which AZ is excluded. She used her credit/debit everywhere else, leaving a nice trail. That it wasn't used in AZ shows intentional behavior to hide that she was there.
This prosecutor is very good.