To me, the various bands playing BS cover tunes demonstrated the untouchable power, uniqueness, and chemistry of the original Black Sabbath. They gave it a shot, but it's impossible to replicate the Titans of Metal.
Of course, being a mid 50s guy who generally lives in the past, I didn't recognize several of the performers and thought several weren't up to par. Nobody cares what an old guy thinks, but my opinion isn't what's important here. This event demonstrated the immense influence that Sabbath has wielded over the the last 50+ years, as manifested by the sheer number and variety of acts paying them tribute. That's a great thing.
I don't have any idea why Ron Wood, Steven Tyler, and others who don't seem to fit the Sabbath mold were there, but I didn't book the show.
Finally, it was cool to see the respect and admiration that Jake E. Lee received from his fellow musicians and fans.