I admit I love having instant access to a wide frequency range, complete with the capability to do bass, mid, treble, chords, soloing, unisons, and whatever. I think that the ideal for everyone is to have as many strings as they can use effectively. I'm a bit ERB fan.
Yet this 11-string bass bothers me, for a couple of reasons. First, my own B strings (on 5 to 7 string basses) are as low as I can hear, as low as my amp can amplify, and lower than my wireless can transmit and receive. WHY add two strings even lower than the B? You can't hear them, and these massive strings cost more all by themselves than a 7-string set costs!
Second, you can't PLAY those two low strings, because the neck is too wide to reach them. I suppose you could play Stanley Jordan style, with the bass sitting on your lap while you tap all the strings, but then why not go with a Chapman Stick? I've seen Jean's videos, and he dedicates one hand to bass and one to treble as far as I can tell. A different technique altogether, and not one I'd particularly want to learn.
So hey, if you can make music out of the whole instrument, using all it offers, great. I can't. I *might* be able to use an 8-string with 16.5mm spacing, string B-E-A-D-G-C-F-Bb. This would let me use standard technique up to about the 14th fret (I have large hands). But once the neck is 8 inches wide, I'm outta here.