Well these terms are often used interchangeably to refer to real life games you play with other people in the real world. Things such as scavengner hunts, spy games throughout a city where we setup scenarios very much akin to what the fantasy of being a spy or an adventurer is like, or how they expect it to be from movies. We try to recreate the fantasy and excitement of being someone like James Bond or Indiana Jones or Nathan Drake as closely as possible. We would not be using UE4 during the games but to prototype or playtest systems before we develop them a game engine like UE4 would be very benificial