Umm... kindlegen is the same:
The reason I wrote out the steps is because a lot of Mac users are not adept with Unix like you and me, and basically cry foul when you tell them that a command-line program is a "Mac app". For a lot of these folks, naming something a "Mac app" implies a fancy GUI. You should really go through Amazon's Kindle forums to see posts dating back to when kindlegen for the Mac was released (in March IIRC). There was a lot of howling and moaning with claims like Amazon does not know how to make a Mac app or that they should put more money into developing proper Mac apps (nothing personal).
I would not be surprised if they had the same reaction when you show them calibre. Calibre is a great app, no doubt about it, but Mac purists will claim that it is not a genuine "Mac app" because it does not use Apple's GUI frameworks (I think it uses Qt), and does not follow Apple's UI guidelines, or something like that which does not affect the functionality and usefulness of calibre.
I hope this does not start a flame war. Lots of people do not know the difference between defence and allergy.