I considered a fanless PSU when I bought my current set-up, but at least back then I didn't find them cost-effective: for a cheaper price I could buy a higher-rated, at least as efficient model from the same manufacturer, and even though it has a fan, it is equally not making any noise in most use cases because it's not running. (I've never bothered to find out when it turns on; later on I added an external GPU to my case, and when its fans start -- not in desktop use -- you can't hear the PSU fan anyway, although I certainly wouldn't mind it running when the case temperature goes up, which it certainly does in certain use.)

Speaking of silent computing; unfortunately my monitor is "louder" than my PC in desktop use for most brightness levels. Anyway, personally I've given up the goal of doing a solid-state PC; a single fan chosen correctly in a case is virtually silent and makes the cooling design much easier; in my experience most PSUs and GPUs produce similar amounts of noise even without fans (and with bad luck, they can be worse).