1970 Duster Starter Wire Wiring - Does it Matter?

The original owner mounted the battery in the trunk and ran a 2AWG wire straight to the starter. Then he ran a wire from the top push on lug on the starter to the relay and piggy backs on the same lug back to the battery. Why he did this wire I don’t know but I can understand why he wanted to run that heavy wire to the starter. Anyway, is there an issue with this? It is safe to run it this way? If you say no, what is the safety risk? If you think it’s safe, where can I run the smaller wire to rather than all the way back through the car? Thanks in advance for your reply.