I like the idea, and as an exclusive fingerstylist I would find that extra string is extremely useful. You can have as many strings as you want these days with custom bridge and pickup builders. Getting them to have a nice and even timbre is another story and involves some logistics.
I’ve been working on more fingerstyle jazz lately, and watching Lenny Breau and other guys who played 7 string electrics, I can see the advantage….
When arranging chord-melody tunes, you generally want to keep the melody line on the upper strings.
Having an extra “high” string makes this easier, you have extended range.
With some standard melodies on 6 strings, you end up using the entire fretboard if you want to keep the melody line “up
However, I’m far too much of an old dog to be learning new tricks… I still have my fingers quite full with 6….