The Olympia is one of my favorite shows - for a number of reasons. First, it is closer to home for me (since I live in the Los Angeles region). Second, it is mostly dedicated to bodybuilding, fitness and figure, and this represents more of the industry in which we are in, in comparison to the Arnold, which had cheerleading, 10K run, table tennis, archery, etc.
If you have never been to one, you are definately missing a lot, and that is a wonder that you can even comment on it if you don't go to it. Many people don't go to the Mr. Olympia show, but go to Vegas for the fun, and for the expo So break it down - you have the expo, you have the shows.
The expo, which is at the Las Vegas Convention Center, is great if you would like to meet some of your favorite competitors. Many are there. Also lots of booths and stuff to check out. For $10, come on already.
The Olympia show is great if you want to see a bodybuilding show featuring some of the best in the world. While perhaps $100 a ticket is high, to see some of your favorite competitors compete in the best of the bodybuilding shows is cool. Hell, people spend $1,000 for ten minutes for a boxing match. It is the hype, the fun of actually going to a show, etc.
And lets not forget this is Vegas. Catch a show from one of the hotels another night, go check out the city sites, etc....