Currently a limitation of NPC device is that it cannot break/damage the environment like Creatures can, so it would be nice to have an NPC Character type for Creatures so that we can allow that to happen (and generally the behavior of Creatures is something lots of custom AI characters need, like navigating to a player and destroying obstacles in their way to get there, if they are breakable by prop manipulators or in general).
Thank you for your feedback. While I cannot guarantee a response, I can confirm that this has been forwarded to the appropriate team.