Hardcover books are fairly expensive these days and to read one requires a significant commitment of time in our busy society. So I want to make sure that when readers buy one of my books they get something they're familiar with.
Your position never gives you the right to command. It only imposes on you the duty of so living your life that others can receive your orders without being humiliated.
If a trip is worth taking, members of Congress should be prepared to justify paying for it out of their office accounts.