Honestly, I have been questioning this for years until i discussed it with many city inspectors city-wide. The purpose is to assure that the ground wire is interconnected but as well as connected to the outlet.
now, one time an inspector asked me to put ground clamps on the ground wires because there was no wire nut that was holding them together but they were twisted together and then one wire went to the outlet. that inspector did not like that. the other 100,000 houses i have worked on, the inspectors had no problem. so i asked a few inspectors after what they think about that inspector that made me put ground clamps on all the grounds and they said it just depended on the inspector.
short and simple as long as the ground wires are connected tight and has strong continuity between the ground and neutral, then your safe. dont worry about it. the electrician still knew what he was doing.