No they are not the ultimate hi-fi speakers. Well designed ones can provide clean SPL at standard listening levels unlike many small inefficient speakers and, again if well designed, can provide an even narrow directivity which can work well in acoustically poor rooms particularly with studio music which tends to benefit less from spectrally well balanced reflections. If used for the low frequencies below the Schroeder frequency they can bring benefits with respect to room integration but the cost in terms size, expense (and visuals for some us!) makes them irrelevant for many.
When I lived in Germany there was more of them around compared to here but a fair few of the expensive blingy audiophile ones, often in bright colours like red, yellow, orange,..., were not well designed. If you have the space and money I would suggest making sure you heard well designed examples before deciding they are not for you. They can work well particularly if designed to integrate smoothly into the corners of the room to remove all early reflections and then crossed in front of you to help image stability.