That will just sound like lip syncing unless the cover band undergoes some heavy cosmetic surgery. The fun of a cover band is watching a rendition of a song where the band are being themselves.
People aren't going to the Van Halen Tribute Show because they're really excited to see John Smith's creative reinterpretation of Eddie's guitar solos.
I’m not sure how fun the concert would be – you’re right about that – but tech like this is definitely has the potential to transform many facets of the entertainment industry.