This is actually a good strategy that I will try to remember to end conversations with people I don't want to talk to but can't physically escape. 
Seriously, when you have a good relationship with someone, long silences are fine, and even treasured. It's those stranger/acquaintance conversations that expect constant back and forth talking - a nonstop exchange of "pleasant nothingness" and "empty pleasantries". Many NTs are not good at doing it either, nor do they want to. But the more you do it and practice it, the easier it becomes.

Seriously, when you have a good relationship with someone, long silences are fine, and even treasured. It's those stranger/acquaintance conversations that expect constant back and forth talking - a nonstop exchange of "pleasant nothingness" and "empty pleasantries". Many NTs are not good at doing it either, nor do they want to. But the more you do it and practice it, the easier it becomes.