The 7 string guitar Steve Vai invented

I've had my sceptisms on that 7 string guitar Steve Vai invented the 7 string Ibanez guitar. It started becoming trendy with nu metal musicians and also musicians in watered down experimental Mr Bungle meets a side project band of Mike Patton clone wannabe bands.  But on the other hand Steve Vai used a 7 string guitar to record Whitesnakes Slip of the Tongue and his solo album Passion and Warfare. When Steve Vai invented the 7 string guitar did it have more of a positive or negative influence on the music landscape?