Freight often contains multiple artifacts. Container would have been a nice word, but it's taken. ;)

I tend to agree, the abstraction from common language (e.g. artifact) is fun because it stays on theme with the "kargo" name but can make it difficult for new users to understand what is happening. I've always loved that in Argo CD, it's just an Application. No special name for something users are often going to refer to.

Kargo (cargo) and Freight makes sense no?