You can't explain why anyone would use a Leica.
I know the jokes about rich doctors and trophy cases, in the past probably made a few myself.
Then I bought an m8 mostly on a whim and have used it from day 1. Not everyday, or every project, not always for what it should be used for, but for some reasons when I use it things turn out pretty.
I have people ask me what "camera' they should by and I say an M8. It's now cheap, doesn't require a dozen lenses, it isn't logical, but it will force a beginning photographer to make a photo rather than just take a photo.
The only complaint I have with the m8 is it doesn't tether and it shoots a beautiful file with studio flash, though nobody would probably use it for that except me, but it does love flash.
I have to admit I have a true fondness for Leicas, enough where I bought an S2 to use for commerce. I haven't got my head around the s2 file like the m8, but I'm learning it and I guess learning to love it.
I don't think Leica will ever make an easy to use, logical cost effective camera, but on the other hand, I don't think any camera gives the pleasure of a leica, but as always that's up to personal opinion.