I think it is a bit of ambiguous phraseology.
If I was being pedantic and said route direct, I would mean go straight there. If I said own navigation to xxxx, then it would mean I would not care if you deviated from a straight line.
I have heard some people use "resume own navigation direct to xxx"... If it's own navigation, surely it is not always direct!!
I would never base separation on any of the above though.