I assume that the OP means the Leica M's, but there is another option if someone is curious about Leicas and wants to see if they are "worth it" - the Leica R's. Used film bodies are very affordable and many lenses can fit onto Canon bodies with an adapter. The R system also has the usual fisheyes, wide angle, super telephotos etc. The lenses are also good to use on mirrorless cameras.
But to answer the query in general, Leica M's are great for travel, street shooting, portraits and landscapes. They are fairly well made, reasonably compact, portable cameras and many of the lenses are at least equal to Canon L lenses in relation to image quality. If the cameras and lenses were selling for less than half of what they currently sell for, there probably wouldn't be much debate. But selling a lower volume, niche product, I can understand why Leica portrays itself as a luxury brand and aims to keep their price high. Though, to me, I think you pay a little too much for the branding, mystique and mythology. But then, Leica did "invent" photography...https://www.youtube.com/watch?v=B-NzDnlOgIw