It simply means that the manufacturers have a different opinion than you do. They put them on there for several reasons, which I've already explained. It keeps the valve clean, provides protection, and it certainly looks better. Two out of those three reasons are practical, the other cosmetic.

I don't find them "fiddly" at all. Screw on, screw off - easy. I don't get flats very often, and also can't relate when someone talks about the need to top off their tires every ride. (Is that a tubeless thing?) I also don't worry about dropping them and chasing them around on the garage floor. Even if you do drop one and it rolls behind the workbench, just grab another one from the bin. I buy the silver ones (to match the valve stem) by the dozen, for mere pennies. They're as close to being disposable as it gets.

In keeping with the spirit of this thread, I contend that the "I'm too cool to bother" attitude is just posturing. And valve stems without caps just make a bike look ghetto.