Well the lair is where the crew is based. It's not easy to just pick up and move the lair. You'd have to make deals with other factions in the new area as you're intruding on someone else's territory.  you'd also fiction wise be leaving behind turf you've managed to take control of or liberate and have to pack up and move all your stuff.<br/><br/>On the same token though, there's nothing stopping us from taking jobs in other districts and I assume we will be at one point. But dealing with things that are close is a lot easier fictionally then having to cross the entire city to get to the other district to do a job. If you look at the map in the player kit you'll see Silkshore and Nightmarket are on opposite sides of the city. There's also bonuses from doing jobs in your preferred protection ground because you know the area really well as that's where you spend most of your time and your crew knows the area like the back of their hand.<br/><br/>Basically choosing one doesn't exclude the other from ever being used but selecting our lair and protected grounds lets us say this is what we want to focus on. After all the crew can't be everywhere at once and there's a lot of factions who want to maintain control and grow their influence too. Using one of the most famous comic book vigilantes as an example. Gotham is Batman's protected ground and the location of his lair. He knows the city better than anywhere else and knows who all the players are. He might go to Metropolis every once in a while  to help with a case or follow a lead there  but he doesn't know the area as well and in the end he always comes back to Gotham. It's his home and what he knows best.<br/><br/>Hope my example makes sense. I'm sure someone else will correct me if I'm wrong but that's my interpretation of things.