Panniers and fenders provide the tangible benefit of making cycling more enjoyable when riding with a load or in the wet, respectively, yes? At least for some people, anyway. Similarly, clipless pedals provide the tangible benefit of make cycling more fun when sprinting, hammering, climbing; basically going all out and getting your aggro on. At least for some people, I think.
I'm with you on the platforms, Adam. I find the added power during hard riding that is provided by clipless is less of a benefit to my personal cycling experience than being able to wear whatever shoes I want, the ability to move my feet around if I want to, and not think at all about getting on or off of the pedals. But that's just me, and I almost never hammer anymore; I like to relax and cruise. People's preferences about how and what their cycling experience should be is so varied that for a lot of bike issues, the only to know for sure what they want or what they'd like is to just try it for themselves.