Deigh, if thats where you started from, then my hat is off, and kudos to you for such great strides in getting back to playing - my deficits are tiny compared to yours, and many of the friends i've made here. I've always been an active guitarist - two of the guys in my current band used to play with me in a previous cover/party/rock band - we did about 12 years around Portland. Now we're doing our own music, its not everyone's cup of tea, but we have fun!
I certainly used to be in the accomplished shredder levels - I dont have the time to practice to maintain that level, and a little of me is worried that the left hand / arm fretboard deficits mild as they are, will impede me getting back there too. To most other players and audience alike, they don't or wouldnt notice the difference. But I know i'm 'off' 10% or whatever. I also have a brain / rhythm process latency that I've become more aware of that I am sure wasnt there before. I have to work really hard now to be on the beat, and not a split second behind it. Again, most wouldnt know, but I know and it is freakin' annoying!! I dont get frustrated or depressed about it anymore. its over two years now since my event, and i'm getting okay with the new me.
Your device looks cool! I get it... how does the pick stay attached to the thumb loop? Can you put any ol' plectrum in there? Your grip style looks like the classic style... i hold my pick differently - do more with the index and middle fingers which gives me more attack flexibility - but stops me doing pick and fingers things, trade offs.
I would think your thing would be useful for many guitarists styles though - at the minimum it would stop the dang pick flying out yer fingers on a dark stage!! hahah!