Sometimes I'd say a greater stage presence is worth more than an indiscernible hit on tone in a venue with so very many other variables (mic'd up cabs, for one...) which will all have far, far greater impact on tone.
If there's one thing I can't stand about a lot of live performances, it looks as though the guitarists are often superglued to the spot, and they seem afraid even to mosh out while playing for fear of some imaginary explosive jacket. However good their playing is, this often makes them a rather boring spectacle...