A: Is it the room?
B: Of course!
B: I will not be able to sleep in that landfill.
A: The theater always sends the authors there.
B: You would never let Vinaver or Yasmina Reza stay there.
B: You are not in it for nothing.
B: I'm not here for my pleasure.
B: I am invited, but I also have work to do.
What does "You are not in it for nothing" mean?