I'm fairly new to ExtendScript and was curious as to whether it is possible to insert a line into Illustrator using the Line Segment tool and not as a PathItem?
I couldn't find anything in the documentation nor any similar queries on whether this could be done.
No, it's not possible to use the Line Segment tool through ExtendScript.
For more on drawing a line:
can you show what you're trying to draw? and explain why a pathItem is not an option?