Exactly. It's all about the type of experience you want to have. Some people are rotor heads. Some people like the war birds. Some people like the high tech stuff. And weird people like me like being the underdog in a casually-powered (to quote a Mudspike review) trainer jet like the C-101.
Sure, you can do pretty much everything in an F-18 that you can in a trainer, but practicing flight fundamentals just seems more "genuine" in a trainer. Something very satisfying to me about properly setting up your NAV radios, setting up your course lines, making sure your HSI is properly aligned and your gyro erected, struggling to keep a set altitude, making sure you don't exceed engine temp. Then there's the combat part. I get a lot more of a thrill when I get a bomb delivery just right through proper speed, dive angle, and sight depression.